What is the matter with this dahlia?
Q. These two dahlias started out exactly the same but one has developed foliage that is contorted, the veins of the leaves are turning yellow and there are yellow spots on the leaves.
A. The dahlia above has a virus. There are a number of viruses that can affect dahlias. It appears to be mosaic virus. A virus can be transmitted from infected seeds or tubers or can be carried from one plant that is infected to another by aphids or thrips. Unfortunately, there is no cure. It is important to dispose of the plant. Do not compost.
Hanu Pappu. Dahlia Mosaic Virus: A pictorial guide to symptoms and diagnosis https://dahlia.org/wp-content/uploads/2018/01/ADS-DMV_Symptoms_Slides.pdf
Meadow & Thicket. Dahlia Virus(es):What you need to know if you love dahlias https://meadowandthicket.ca/wordpress/dahlia-viruses-what-you-need-to-know-if-you-love-dahlias/
Dahlia Virus disease https://pnwhandbooks.org/node/2628/print
My orchid is growing leaves and roots near the top of an old stem. Can I start a new plant?
Your orchid has created a plantlet or keiki (the Hawaiian word for baby). Keikis can occur naturally when growth hormones accumulate at a node on a flower spike. Sometimes it can be a sign that a plant is under stress and is trying to reproduce while it can.
Before removing a keiki, it should have several leaves and a couple of roots that are about 2-3 inches in length. If it is removed before this stage it will have a hard time surviving. You can lightly mist your keiki to keep it hydrated while it develops.
To remove the keiki, sterilize a sharp knife or sharp garden shears and cut into the cane just above and below the plantlet. The open wounds on your orchid and keiki should be treated to prevent fungal infections. Cinnamon is a natural fungicide or you can buy a commercial product at your local garden centre. Be careful not to expose your new plant to too much direct sunlight immediately after transplant. Once the keiki shows signs of growth, you can begin to gradually increase the amount of light it receives. Generally, it will be 2-3 years before your new plant will produce flowers.
The American Orchid Society has some helpful video clips to demonstrate how to remove a keiki. http://www.aos.org/orchids/aos-video-library/removing-a-keiki.aspx. There is also a video on how to pot it up. http://www.aos.org/orchids/aos-video-library/potting-a-keiki.aspx
Why doesn’t my African violet bloom?
Key cultural practices African Violets need to thrive and bloom are:
- Light – African Violets like bright indirect light but not heat. They need 10-12 hours of light a day and at least 8 hours of darkness a day to produce flowers. They should be sited about 12 inches from a bright window or 12 inches from a grow light. African Violets bloom best at temperatures 18-20 C. In winter, if your plant is too close to the window, it may be too cold.
- Growing medium and pot size – African Violets like a porous mix of sphagnum moss, vermiculite and perlite. You should be able to push your finger through the growing medium down to the bottom of the pot. Your pot should be one-third the diameter of the plant. A shallow pot is good for drainage and root aeration. The crown of the plant should be just above the surface of the soil. If your pot is too large the plant is unlikely to bloom. Repotting is an easy fix. Sometimes African Violets become vegetative and repotting can encourage them to bloom.
- Moisture– African Violets like to be just right, not too wet and not too dry. You can water from above or below. Keep the foliage dry and make sure your plant isn’t sitting for water for longer than 30 minutes. Use room temperature water and if you have chlorinated water make sure it sits overnight before watering. Never use soft water as it is too salty. If your African Violet gets flower buds but they dry up before opening, humidity may be a factor. The ideal humidity for African violets is 40%.
- Fertilizer– There are a number of fertilizers designed specifically for African Violets. One with a high middle number indicating that it is strong in phosphorous is ideal.
If your African Violet has never flowered and changing cultural practices does not encourage your African Violet to bloom it may be the genetics of your plant. Consider looking for a new African Violet with a symmetrical shape, firm green leaves and lots of flower buds.
Resources for African Violets
African Violet Society of America http://www.avsa.org
Stork, Kent & Joyce. Beginners Column: Secrets to Blooming Success in African Violet Magazine, July/August 1992 http://avsa.org/sites/default/files/files/Secrets%20to%20Blooming.pdf
University of Georgia Extension services https://extension.uga.edu/publications/detail.html?number=C660&title=Growing%20African%20Violets
What can I grow in clay soil in shade near a fence?
The first step is to determine what type of shade you have.Is the shade from the fence? Is it from nearby trees or shrubs? Are you dealing with tree roots? If you are dealing with tree roots the shade is likely be dry shade as the trees will use most of the moisture in the soil. Observe how much sun the bed receives at different times of the day. This may change depending on the time of year. It is helpful to know if the area is in deep shade or partial shade when selecting your plants.
If you have clay soil, it is possible to improve the soil texture over time by adding compost or shredded leaves to the top of your soil. After planting you may want to apply an inch of mulch.
When you plant along a fence be sure to consider the size of the mature tree or shrub and allow enough space from the fence. Evergreens provide year-round interest. There are interesting dwarf conifers you can investigate. Vines also work well to soften a fence.
For the lower level closer to the front of the bed consider Hosta, Perennial geraniums, Brunnera and Heuchera. Foliage for Hosta and Heuchera come in a variety of colours to provide interest throughout the seasons. If you have partial shade you may want to try some day lilies.
For further ideas check out some of these resources:
Cramer, Harriet L. (2000). A Garden in the Shade. New York: Friedman Fairfax.
Hodgson, Larry. (2005). Making the Most of Shade: How to Plan, Plant, and Grow a Fabulous Garden that Lightens Up the Shadows. Emmaus, PA: Rodale
Best plants for problem clay soils: trees and vines. William T. Kemper Center for Home Gardening, Missouri Botanical Garden https://www.missouribotanicalgarden.org/Portals/0/Gardening/Gardening%20Help/Factsheets/Clay%20Soils%20-%20Trees8.pdf
How can I prevent slugs from eating my hostas?
Oh, how I wish there was a definitive answer. There are many methods circulating but few that are really very effective.
- Beer traps are one method. You fill a container with beer and place it so the top is soil level. The slugs are attracted to the smell, crawl in and drown. Be sure to empty every day.
- Ammonia treatment just as the hostas are emerging is another way. Mix one part ammonia with ten parts water and water around the hostas just as they begin to emerge in spring.
- Hand picking around dusk and beyond or on a rainy dull day is effective but ….. perhaps distasteful. Use long handled tweezers, a headlamp and a bucket of soapy water. Throw in the composter when you have enough. The soap is necessary; otherwise, the slugs will crawl up the sides of the container.
- Slug bait that is not harmful to other animals is recommended by some and can be effective but what does it do to beneficial creatures in the soil?
- A useful article that lists ways of dealing with slugs is: http://How to Get Rid of Slugs 8 Organic Control Methods www.savvygardening.com
- Sean James, a well-known horticulturist in Ontario, says he loves hostas and doesn’t have a slug problem because of the biodiversity in his garden: http://View of Sustainable Gardening; Landscaping for Biodiversity www.neviews.ca
- I am a convert to Sean’s idea of biodiversity in the garden and believe I have noticed fewer slugs as we attract more birds and other creatures to the garden.
- A few years ago, after a particularly bad slug year, I dug up the the hostas with the most damage and gave them away. If hostas have a thicker substance, they are more slug resistant. One of my favourites, June, seems to have far less damage than some other thinner ones.
- I do love mini hostas and they can be devoured quickly so in the places where I have them, I use beer traps and handpicking.
What can I plant to add colour to my shade garden?
There are so many, many possibilities, it is difficult to know where to begin. Let’s assume that your shade garden has many of the dependable favourites such as hosta, ferns, and Lady’s Mantle, and you are looking to add a shot of colour and brightness to it.
The easiest and fastest way is to add annuals such as Impatiens, Pansies, Coleus or Wax Begonias, directly into the ground, or in pots among the greenery.
But, let’s investigate longer term solutions and define “shade”. If your garden receives less than 6 hours of direct sunlight, it is shady. Fewer than 3 hours of sun is considered full shade. In between 6 and 3 hours of direct sun per day is considered part shade. Keep in mind that the hours of sunlight will change with the seasons. Before the tree leaves are fully formed, you may have an area that is in full sun. By August as the sun changes its path, you may have an area that transitions from part shade to full shade.
Following are shrubs with interesting leaves and/or flowers
- Mountain laurel (Kalmia latifolia) has glossy leaves and clusters of rose, pink or white flowers with purple markings. Blooms in June.
- Hydrangea and Climbing Hydrangea are both shade tolerant, with many different species. Easy care, with lots of flowers.
- Carol Mackie Daphne is a beautifully scented shrub which grows to about a metre in height. They have delicate blossoms, followed by berries and variegated leaves. The shrub is not a good choice if you have small children, since it is poisonous.
- Serviceberry (Amelanchier species)are native to Canada, with white blooms in spring and edible purple berries in mid-summer. Some grow as high as 12 feet, but others are attractive, shade-loving shrubs of a more modest size.
- There are many colours and species of Rhododendron and they love semi-shade or a dappled sun area. They need good drainage and shelter from heavy wind.
Perennial flowers for shade
- Canadian Bunchberry (Cornus canadensis) is a low-growing plant and makes a good ground cover. Its white flowers look like dogwood blooms.
- Bleeding heart (Dicentra spectabilis), Dutchman’s breeches (Dicentra cucullaria) and Fringed Bleeding Heart (Dicentra eximia) are all early blooming plants which add colour early in the season.
- Foxglove (Digitalis purpurea) shows off its tubular bells on spikes and will tolerate clay soil. It is happiest in shade and is a biennial. That means it blooms alternate years, but since it self seeds prolifically, you’ll always have some blooming. They come in many different colours and all parts are poisonous.
- Bugbane is also known as Black Cohosh, snakeroot, Cimicifuga and fairy candle.Its Latin name is Actaea racemosa. The wands of white flowers sway above ferny leaves, and have a honey-like scent. Since it is a late blooming, native perennial, it is important for pollinators. Bugbane can definitely add interest to a dark corner of your garden.
- Jacob’s Ladder (Polemonium caeruleum), is another hardy perennial flowering plant. The plant produces cup-shaped, pink, blue or white flowers, can have variegated leaves, and thrives in shade. It will get ‘sunburn’ easily, but is an easy-care addition to a shade garden.
- Rodgers Flower (Rodgersia spp) produces red, white or pink feathery flowers in a spike, above heavily textured leaves. They are deer and rabbit resistant and love moisture. They can get quite large, and would make a great ‘back of the shade garden plant’, blooming in early summer with a fine fragrance.
- As you can see, no shade garden needs to be dull. Here are more shade loving plants for you to explore: Ligularia, Stella D’Oro, Astilbe, False Dragonhead, Heuchera, Hellebore, Lungwort, and Primula.
Here are some images of some of the flowers mentioned above:
How do I get rid of hogweed?
Giant Hogweed (Heracleum mantagazzianum) looks like cow parsnip or Queen Ann’s Lace on steroids. It can grow to 6 metres in height and more than a metre wide. If you have any of this invasive plant, LEAVE IT ALONE. All parts of it are extremely poisonous and can cause painful, burning blisters on the skin of humans and animals. Getting the sap in your eyes can result in blindness.
Here is a link to a fact sheet from the Upper Thames River Conservation Authority. It will help you to identify giant hogweed.
Contact them if you are in the Stratford/London area. Email: email@example.com 1-519-451-2800.
If you live in another area, contact your local City Hall. Do not attempt to remove giant hogweed yourself.
How can I get rid of goutweed (Aegopodium podagraria)?
Goutweed goes by various names: bishop’s weed, ground elder and others which are unprintable. It is one of the most common groundcovers used in our gardens and comes in variegated and solid green species. The bloom is white and umbel shaped. It spreads out in all directions thanks to its numerous horizontal underground rhizomes. It’s very aggressive, choking out other vegetation and even preventing trees and shrubs from germinating. When it escapes into woodlands or nearby fields it causes damage to the environment as it chokes out everything else.
Control: As with all aggressive non-natives, it is impossible to eliminate goutweed. Control and prevention of new infestations is the best we can do. A tiny bit of rhizome, which can penetrate 60 to 100 cm. deep, will re-sprout. Digging can work for a small area, if you keep on top of it. Chopping and rototilling will make it worse.
Solaring is the best method of killing off a large area of goutweed. This is basically cooking it in the sun. Mow or hand cut the area as short as possible. Then cover it with black tarp (not landscape cloth). Cover the tarp with mulch, stones, soil, old car parts – whatever you have to hand. BUT remember you’ll need to look at it for at least a year. It will take that long for the energy in the weeds’ rhizomes to be depleted and for the plants to die. It could take longer! You will need to watch that area and the surrounding area for ‘pop-ups’ of new goutweed plants forever.
Some people say selling up and moving is the only way to really get rid of goutweed.
For more information:
Can mulch be applied right on top of the flowerbed and will bulbs be able to push through the mulch?
The answer to both questions is “yes”. Mulch has many benefits. For example mulch suppresses weeds, keeps soil warm and insulated from winter temperatures and it helps the soil stay cool in summer. It provides nutrients and improves soil structure to both soil and plants. Mulch can be applied in both the spring (2-3 inches) and in the fall. In the spring do not apply mulch until the plants have popped their heads above the soil- depending on your area it could be late April early May. Please do not put the mulch right on top of the plants. Keep the mulch approx. 2-3” away for the stem or bulb as this will prevent moisture, fungus and viral disease attacking the plants. When selecting a variety of mulch try to select a lighter mulch rather than a heavier and bulky mulch such as bark chips as it makes it more difficult for the plants, especially bulbs, to push through the soil. As the fall comes around have a look to see how much the mulch has decomposed into the soil. If you have to top up the mulch only do so after the ground is frozen. The main idea behind winter mulching is to keep the ground frozen by shielding it from the warmth of the sun. A steady temperature will keep the plant in dormancy and prevent it from triggering new growth during a brief warm spell. Tender, new growth too soon will just result in more winter dieback. Mulching will also help conserve whatever water is in the soil. Keeping your garden beds watered right up until the hard frost is also very important.
What kind of light should be used for growing seedlings?
There are three options you can use for lighting: windows, fluorescents or LED Lights.
The ideal scenario for window lighting would be to have a south facing window with at least 8 hours of day of sunlight. Note you will have to rotate the flats every day or the seedlings would be become long and lanky.
An LED lamp or LED light bulb is an electric light for use in light fixtures that produces light using one or more light-emitting diodes
- Long life
- Low heat output
- Low energy use
- Greater spectrum of light
- Can be plugged into standard outlet
- Bright purple/pinkish glow- can now get them in white as well
- High initial cost
Fluorescent lights are a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow.
- Low upfront costs
- Good coverage
- Short life
- May “burn” plants if placed too close to the plants
- Not energy-efficient
If you have a large enough area to put your seedlings on a preferably south/ southwest facing window ledge, this may not work if you have an apartment or limited amount of windows. The bottom line is you can’t go wrong using either or Fluorescent or Led Lighting . I believe LED is becoming the new standard and they are much cheaper now than they were 5 years ago. For example, you can get a 4ft white LED light for approx. $20.00 .
More information can be found on the following website:
When should I overseed my lawn?
The best time for over seeding cool-season grasses in northern regions is late summer to early fall (September), when they’re growing most vigorously. Spring is the second best time. The warm soil encourages seed germination, cool fall air stimulates growth, and soil moisture stays more constant. Note in the fall the weeds are less active and will not compete as much for space as would be in the spring or summer months.
Very importantly please spend the money to purchase good quality grass seed from a reputable company, Ensure you purchase seeds that are meant to be grown for our Canadian climate as it can make the difference between success and failure.
More information can be found by checking out the following website:
Do you have information about Carolinian species?
Carolinian forests or ecosystems make up about 1% of Canada’s total land area, but include a greater number of flora and fauna than any other ecosystem in Canada. For example, there are 2,200 species of herbaceous plants, 64 species of ferns, 110 species of grasses, 400 and species of birds. In Canada, the Carolinian zone, which is named after the Carolina states in the U.S., is restricted to a small band in Southern Ontario, stretching roughly from Grand Bend to Toronto. Because this is also the most densely populated area of Ontario, much of the Carolinian forests have been destroyed.
Although Carolinian forests are dominated by a mix of sugar maple, beech and oak trees, they also contain rare species such as the tulip tree, sassafras, Kentucky coffee tree and the Pawpaw. Plants that are unique to Carolinian forests include green dragon, pale jewelweed, butterfly weed and wild ginseng.
Over the last few decades, there has been increasing interest in preserving the remaining Carolinian forests in Ontario. Much of this effort has been driven by Carolinian Canada, with other non-governmental and government organizations playing a part.
Carolinian Canada identifies 38 areas that contain examples of Carolinian forests in Ontario, approximately 40,800 hectares. The sites are either owned by conservation groups or managed by private landowners who have entered into land stewardship agreements with Carolinian Canada.
For further information, check out the excellent website of Carolinian Canada at www.caroliniancanada.ca
Are there perennials that can be planted in containers in the shade?
Planting containers in the shade shouldn’t be a challenge and in fact offers a chance to experiment with different varieties of plants. The basic principles are the same as planting containers for sunny locations. There should a thriller plant, one or more filler plants and spiller plants. Colours should be either harmonious or contrasting – meaning either side by side on the colour wheel or opposite to each other.
When planting a container for the shade using only annual plants there is a rich variety in today’s greenhouses. Coleus plants come in a wide range of shades that will mix well with begonias or impatiens and ivy or creeping Jenny work well as spillers.
For truly adventurous plantings, mix perennials and annuals in the same containers for unexpected and exciting effects. A large planter for a shady locale could have a dramatic thriller with a New Zealand Flax, ‘Jester’ (a dwarf cultivar of this tropical plant that boasts shades of green, coral and pink). The filler here could be a salmon flowering impatient such as ‘Magnum Salmon’, and a Coral Bell ‘Red Dress’. An Autumn Fern adds texture and a Japanese Forest Grass would make a spectacular spiller. The perennials in this container can be planted in the garden come autumn. Make sure your container has a variety of texture and fill it generously for a great result.
Making the Most of Shade – How to Plan, Plant, and Grow a Fabulous Garden that Lightens up the Shadows, By Larry Hodgson
The Complete Shade Gardener Paperback, By George Schenk
Container Gardening Hardcover, By Paul Williams and Nigel Marven
How can I get rid of Creeping Charlie?
Creeping Charlie (Glechoma hederacea) also commonly called Ground ivy is a perennial plant introduced to North America by settlers who thought it was a good ground cover for shady conditions. It is now common throughout Southwestern Ontario.
Creeping Charlie can be identified by its green rounded scalloped-edged leaves that are opposite on its creeping square stem and its small purple-blue funnel shaped flowers. The square stem indicates that this plant is a member of the mint family and like most members of the mint family is persistent. The stem will root wherever a node touches the ground.
Because Creeping Charlie thrives in shady moist conditions, one way to discourage it is to change the growing environment by improving soil drainage and increasing light levels. The best method to get rid of Creeping Charlie is physical removal.
Ed Lawrence in his book, Gardening Grief & Glory, recommends removing Creeping Charlie from your lawn in the spring as soon as it is dry enough to rake. First rake in a north-south direction then rake east-west so that you have raked the lawn in a grid pattern. This approach will remove a significant amount of the Creeping Charlie. You can then improve your lawn by top-dressing with 1 cm. of compost and plant a shade grass mix including fescues. You might also want to include some Dutch White Clover. Keeping your grass longer by raising your mower blade will help to create a more vigorous lawn.
Hand weeding is the most effective method of removal from garden beds. After an initial weeding, mulch can make it easier to pull out any Creeping Charlie that persists.
You may find some resources suggesting borax as an organic control for Creeping Charlie. However, research at the University of Wisconsin and at Iowa State University revealed that borax does not provide a long-term control and can cause stunting and yellowing of your lawn and plants.
Lawrence, Ed. and Liane Benoit. (2006). Gardening Grief and Glory: Ed Lawrence answers your gardening questions. Wakefield QC: Tarlock Woods Publishing Inc.
Mahr, Susan and John Stier. April 2010. https://hort.extension.wisc.edu/articles/creeping-charlie/Accessed July 20, 2019.
OMAFRA staff. 2009. http://www.omafra.gov.on.ca/IPM/english/weeds-herbicides/gallery/creeping-charlie.html Accessed July 20, 2019.
OMAFRA staff. 2002. http://www.omafra.gov.on.ca/english/crops/facts/ontweeds/ground_ivy.htm Accessed July 20, 2019.
Why bother planting alternatives to invasive plants?
Invasive plants typically have characteristics which allow them to spread quickly and to have the ability to form dense colonies which force out native vegetation. You have to grudgingly admire them, because they almost always have high annual seed production, will grow anywhere, will spread quickly underground and have no predators to munch on them. Often, their seeds can lie dormant for years, then germinate. A tiny piece of an invasive root can regenerate, and many of them emit chemicals which prohibit other plants from growing near them, called allelopathy.
“…some introduced species can disrupt the natural balance of our ecosystems. These invasive plants take over habitats, creating a mono-cultural environment (i.e., one species only) and depleting our native plant populations. They may also cause erosion in woodlots and reduce the beneficial mycorrhiza (fungus) in the soil that native trees and plants depend on to survive. They can hybridize with native species, thus depleting the genetic stock of our native flora. Native wildlife also have limited use for these plants and thus their food, cover and nesting sites are decreased when alien plants take over.
Once these plants are in our natural environment they can be very difficult to control. Many have aggressive root systems, produce an abundance of seeds and/or do not have any natural enemies in this area.” http://thamesriver.on.ca/watershed-health/invasive-species/
Example: An area of non-native, invasive plants, such as Garlic Mustard (Alliara petiolata) will grow quickly and out-compete natives such as Trilliums in a woodland. Thus, the native insects above and below the surface have nothing to eat. The whole ecosystem changes.
Garlic mustard, Photo courtesy of By Tony Atkin, CC BY-SA 2.0,
Another example: You many have noted tall grasses growing along roadsides and in wet areas. The invasive phragmites (Phragmites australis) outcompete native wetland plants with its thick root system, prolific seed heads and height (shades other plants).
For more information:
Can I put my vermicomposting worms in the garden?
The short answer is yes, but…
Vermicomposting is the process of using earthworms to make compost. There are now many options for having a composting system indoors. The advantages of starting a vermicomposting system is that it allows you to make organic fertilizer year around. It also allows people without access to a compost bin to recycle some of their food scraps, and it makes great homemade potting soil.
The type of worm used in vermicomposting is the Eisenia fetida, also called the red wiggler, red worm or compost worm. The red wiggler is an epigeic worm, which means that it lives above-ground. Unlike the anecic worm, such as the earthworm, dew worm or night crawler, it does not burrow. Epigeic worms live in surface litter and feed on decaying organic matter.
If you put red wiggler worms directly into your garden, they will likely die because they have no easy food source. To help them survive, you can build a compost trench and add the worms to the trench. You can also add the worms to an existing compost pile, but you will need to modify the compost pile so that it is not too hot or too dry for the worms. If you add the worms to a compost pile, you will want to mimic the environment in a vermicomposting bin. If the bin is too hot or too dry, the worms will move to another location, or die.
How to build a compost trench
Dig a trench in your garden 15-20 cm deep and any width. Add a layer of shredded newspaper or cardboard to the bottom of the trench and a layer of kitchen scraps along with some garden soil or shredded leaves. Put your red wiggler worms on top of this, and add a layer of soil. The worms will decompose the kitchen scraps and the soil will be enriched by their worm castings.
Tips for adding worms to your compost bin
If you want to add your red wiggler worms to your compost bin, make sure that you add more carbon to the bin than you normally would. A typical compost bin should have a carbon/nitrogen ratio of 25-30:1. For red wiggler worms to be happy in your compost pile, the pile should have a carbon/nitrogen ratio of about 50:1. You will also want to make sure that the pile is a little moister than a regular compost bin. Make sure that you continue to add scraps to the bin so that the worms get enough food.
www.compostjunkie.com. An excellent website about all things compost, including vermicomposting.
www.cathyscomposters.com. Good info on vermicomposting.
When is the best time to prune a butterfly bush?
A butterfly bush (Buddleia Davidii) flowers on new growth. If you are growing the shrub for its flowers, the best time to prune a butterfly bush is in early spring, just before growth begins. Using a lopper or a short saw, prune all the branches close to the ground. All that should remain is the stubs.
As with any shrub, you can prune diseased, dead or unwanted branches at any time of year. You can also shape your butterfly bush while it is actively growing. The shrub is very tolerant of pruning.
Once flowering begins, you can increase the growth of side blossoms by cutting back spent panicles or blossoms. Not only does this increase the flower production, but it also prevents the plant from going to seed. Butterfly bush can be invasive and if the plant allowed to go to seed, it may spread in unwanted ways. Since most butterfly bushes are hybrids, the seedlings from a butterfly bush will likely not look like the parent plant.
How do I control aphids?
What are aphids?
Aphids are small, (2-3 mm) soft bodied, pear shaped insects. They have two antennae and a pair of short tubes, called cornices, at the rear of their body. They come in a variety of colours, from green, black, yellow, white and orange. There are approximately 4000 species of aphids worldwide. Aphids overwinter as eggs, hatching in the spring. Most aphids that you see on plants are females and flightless. The nymphs mature in 7-10 days and produce about 40-60 live offspring. About a dozen aphids can generate hundreds of thousands of offspring in a few weeks. Once the population becomes too crowded, some of the aphids will develop wings and fly to new host plants, where the cycle in repeated. Mating between males and females occurs in late summer, when the females will lay eggs that will overwinter.
What do they do?
Aphids damage plants by sucking out the sap (called phloem) from leaves, twigs, stems or roots. Infected plants will have yellow or curling leaves, and will be less vigorous. Aphids can also damage fruit and flowers, causing them to be distorted or mishapen. Aphids are disease vectors, carrying fungi in their mouthparts and transmitting it to the plant. They also secrete a sticky substance called “honeydew”, which can attract a fungus called black sooty mold.
Which plants attract aphids?
Aphids are most attracted to young growth and will rarely infect a healthy and mature plant.
How can aphids be controlled?
Here are the most common ways to control aphids:
- Monitor your plants- watch for infestations and treat them as soon as you see them. Aphids like to hide on the underside of leaves, so make sure you check all parts of the plant.
- Prune off the infected part.
- Crush the insects by hand if there are just a few.
- Blast them off with the jet setting on a hose. Or use a powerful water bottle sprayer. Repeat every few days until the aphids are gone. Make sure to check the underside of the leaf!
- Use insecticidal soap for really heavy infestations. The soap damages the outer layer of the insect’s body and causes dehydration and death. You can make your own insecticidal soap by dissolving a few teaspoons of dishsoap in a in a litre of water and spraying directly onto the insects. Direct contact is needed.
- Some plants have been shown to deter aphids, particularly those with a strong scent. Plants such as oregano, garlic, leeks, or sage may deter aphids.
- Apply a dormant oil spray to trees or shrubs in the late winter/early spring. The dormant oil spray will kill overwintering eggs by smothering them.
- Encourage beneficial insects to your garden. Insects such as lacewings, lady beetles or hover flies will eat aphids. However, if you have a really large infestation, it is unlikely that the beneficial insects will be able to consume all of the aphids.
- Do not overfertilize your plants with high nitrogen fertilizers. Aphids like plants with succulent new growth. Use organic fertilizers such as composts- they release their nutrients more slowly.
- For houseplants
- Check your plants carefully when your purchase them to make sure you are not transporting aphids. Even one is too much!
- Take your plant outside and spray it with a jet of water. If the plant leaves are too delicate for a strong spray, dip the plant in a pail of water to remove the aphids.
- Remove the infected parts of the plants.
- Spray the plant with insecticidal soap, making sure to spray all parts of the plant. Repeat as needed.
- Isolate your newly purchased houseplants for about a month after purchasing to ensure that they are not infected with aphids.
Some odder controls
- Aphids are reputedly attracted to the colour yellow. Place pans of water with yellow food colouring close to infestations. The aphids may be attracted to the water and drown.
- Place yellow double sided tape around the rims of your pots. The aphids will get stuck to the tape.
Looking for more information?
Rhodes, Heather. “Killing aphids naturally”. https://www.gardeningknowhow.com/plant-problems/pests/insects/homemade-aphid-control.htm
Townsend, Lee. “Entomology: Aphids”. www.entomology.ca.uky.edu
What can I grow that will survive near a black walnut?
Black walnuts secret juglone in all parts of the plant with the roots being the most toxic. Plants will be affected by this toxicity up to 50 feet from a mature walnut. Even after a tree is removed it may be several years before the juglone is leached from the soil.
If you want to grow plants that are juglone sensitive, raised beds within that area can work but all debris ie. nuts, shells and leaves must be removed.
There are numerous lists available on line that give names of trees, shrubs, perennials, annuals, vegetables and fruits that have been observed to be tolerant of juglone.
You can have a successful colourful garden with seasonal blooms.
Here are some seasonal suggestions: some of these are species specific so check carefully before buying.
Trees and shrubs: redbud, serviceberry, hemlock, ninebark, euonymous, dogwood, daphne.
Spring: hosta, ferns, bleeding heart, Siberian iris, allium, HelleboresSummer/fall: coneflower, phlox, bee balm, heuchera, anemone, cimicifuga, ligularia, sedum, asters