Buddleja davidii: Learn About Butterfly Bush Care

Buddleja davidii a.k.a. Butterfly bush, Buddleia, or Summer Lilac.

Butterfly bush (buddleia) is a fast growing deciduous shrub. It will get long showy flowers that bloom from early summer until frost.

For best flowers these plants should be grown in full sun but can tolerate a little shade.

In some places butterfly bushes are considered invasive but according to OMAFRA, Ontario Ministry of Agriculture, Food and Rural Affairs it is NOT listed as invasive in Ontario. I would assume it’s because of our cold winters and the fact that it dies back to the ground every winter so the seeds can’t germinate.

Besides attracting butterflies, this plant also attracts other pollinators to your garden. Hummingbirds and bees also love this plant.

Growing in Containers

I haven’t personally tried to grow a butterfly bush in a container yet but from the research I have done there have been many people that have successfully grown them in containers.

However, here are some things to remember:

• Some butterfly bushes can get up to 10’ tall, some even taller so it’s best to stick with the dwarf sizes for containers (Petite Plum is a smaller variety)

• Use potting soil and not garden soil. There is a difference. Garden soil will get very heavy and not drain properly in containers

• They need more water than other plants in containers

• They shouldn’t be cut back until the new growth starts in spring

• They get large roots so it should to be a very large container

• They should be fertilized with a slow release fertilizer in spring

• It will need protection during the winter.

My suggestion would be to plant it in the ground over winter to make sure it survives. If you do over winter it in the pot make sure you wrap the pot in bubble wrap or burlap to help insulate it and move it to a protected area out of the winter winds.

If you want to keep your plant in the container from many years it should be root pruned when it is dormant. 

With root pruning you are doing the same thing to the plant as when you prune the top of it. You trim off a couple inches of the roots which will promote more roots but stops the plant from getting root bound in the pot.

If you do decide to grow one in a pot or are currently growing one please let me know how it does.

Butterfly Bush Pruning

In colder climates they may die back to the ground during winter.  New growth will be visible in early spring around the crown of the plant and sometimes on a few lower branches. You will want to prune everything off above that new growth as it will not produce any new growth.

You can either use pruning shears to remove the old growth or just break the branches off.

If the winters don't cause the plant to die all the way back to the ground, you will still want to do some butterfly bush pruning. Pruning will keep the plant looking great year after year. Prune the plant about 12" from the ground which also helps control the size.

The flowers bloom on new wood so if you have to trim during the growing season it won't hurt any of the flowers.

Your plant will also benefit from deadheading during the summer. This will encourage more blooms throughout the summer.

Varieties of Buddleja davidii 

There are many varieties of Buddleja. Some can get very tall while others will stay short. They come in a range of colours from pink to purple to white and even multi-coloured.

Try the 3-in-1 butterfly bush method. You can put 3 varieties together in the same hole when planting for a multi-coloured shrub. A pink, purple and white Buddleja planted in the same spot would be stunning.

Pests and Diseases of Buddleja davidii

There are not too many pests and diseases that attack the Buddleja davidii but a few to look out for are listed below.

Neglect and drought will weaken the plant and make it more venerable to them.

Pests

Spider Mites – microscopic spiders might invade your bushes. They are very hard to see but controlling them is very easy. Read how to identify and control spider mites.

Root Nematodes – These tiny parasites worms live in wet soil and attack the roots of your plants. If your plant isn’t doing as well as you expect it to do, check the roots. If nematodes is present, the roots will be shorter them normal. Controlling them isn’t easy but mulching and fertilizing your bush might help it.

Diseases

Downy Mildew – cool damp weather can cause downy mildew. It looks like fuzzy gray spores on the underside of the leaves. If you notice this remove any part that is infected and dispose into the garbage. To stop it from coming back only water during the day so that the plant is not wet over night.

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