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Butterfly bush, fluttering and buzzing all around fabulous flowers

Butterfly bush

Butterfly bush key facts :

Botanical names: Buddleja, Buddleia
Common namesButterfly bush, butterfly tree, summer lilac
Family – Scrophulariaceae
Type – Shrub

Bearing – round
Height – 10 to 18 feet (3 to 5 meters), depending on the species
Breadth – 6 to 10 feet (2 to 3 meters)
Exposure – full sun to part sun
Soil – any type
Hardiness – excellent

Growth – fast
Foliage  – deciduous
Flowering : spring and summer

The butterfly bush definitely deserves its name. A particularly melliferous and flower-bearing shrub, it is indeed a paradise for pollinating insects of all runs: butterflies of course, but also bees, hoverflies, bumblebees, etc. Easy to plant, it will quickly decorate your garden thanks to its fast growth and magnificent summer flowers.

Planting a butterfly bush

Buddleja can adapt to all types of soil. Its only real requirement is exposure: full sun is, by far, preferable. Nonetheless, it will still survive in part sun, but it won’t grow as lush.

When to plant Buddleja ?

The butterfly bush, in a perfect world, would always be planted in fall. Planting that takes place in that season indeed lead to better settling in and faster growth for plants. It gives them a few months to grow new roots before spring and summer come around (when water often is wanting for days on end).

How to plant a butterfly bush

The size and shape of Buddleia make it compatible with planting in small gardens, and even in a container if you so wish.

Directly in the ground:

After determining the right spot for your butterfly tree, just follow these steps to plant it:

  • White butterfly bush plantedDig a hole about 12 inches (30 cm) deep.
  • Layer some soil mix along the bottom and mix it in with garden soil.
  • Remove the pot from the shrub’s root clump, and break the clump apart, extracting roots in a spiderweb-like pattern. This step will spur root growth towards the outside of the initial root ball.
  • Settle the butterfly bush in its hole, and backfill it without burying the portion of the stem that connects to the roots: the root crown. For guidance, lay a rake handle or straight stick across the hole: it will mark normal “ground level”.

Butterfly bush in a pot:

Thanks to its tight, bushy bearing, Buddleia does well when planted in a pot to decorate a deck or terrace. Planting is quite similar to when you’re planting in the ground.

  • Select a large container, and, if possible, with a water retention system (to reduce the need for watering).
  • Make sure the pot has drainage holes underneath it. If there aren’t any, make 3 or 4 with a hand drill and a large drill bit (for cutting ceramics).
  • Spread a drainage layer, taking care not to clog the water drains. You can use gravel, clay balls, etc.
  • Fill the pot with soil mix, and top it off with plant-based soil. If you want, you can amend the substrate with vermiculite (or perlite) which enhances drainage while retaining some of the moisture.
  • Plant your butterfly bush following the same steps as for planting directly in the ground.

Butterfly bush care

Caring for butterfly bush ensures great bloomingDepending on how it was planted, you won’t care for it in the same manner. There is, though, one point that is the same for both: pruning. To keep the shrub dense and compact, you must cut it back the moment all leaves have dropped back.

For the tree planted in the ground, this is the only work you’ll ever have to do.

For a potted butterfly bush, there are a few extra steps:

  • Keep an eye on water needs so that the soil doesn’t get too dry.
  • Add nitrogen-rich fertilizer in spring, and potassium fertilizer in fall. Best go for slow-release, granulated fertilizers so that the shrub has time to absorb the nutrients inside.
  • Repot every 4 to 5 years.

Pruning a butterfly bush


To create new butterfly bush specimens, simply prepare softwood cuttings.

Butterfly bush propagationNote, however, that the butterfly tree very easily propagates naturally through seed.

Since it’s sometimes classified as an invasive species, it helps to be forewarned.

Some studies have shown that certain cultivars like ‘Nanho Purple’ and ‘Dartmoor’ have a high germination rate, whereas others like ‘Black Knight’ and ‘White Profusion’ are slower to spread.

Diseases and pests

The butterfly bush is very resistant. It thus isn’t vulnerable to diseases, and pests don’t seem to find it interesting (apart from aphids, but they’re only really a problem when in very large numbers).

Landscaping uses and companion plants

Landscaping with butterfly bushRegarding possible uses, the butterfly bush has a lot to share: standalone, in a group as part of a shrub bed, in the ground or in a pot; the choice is yours to make!

Buddleja isn’t very demanding, so you can pair it with many other types of shrubs like lilac, photinia, forsythia, hamamelis that will provide colors and blooms when the butterfly tree doesn’t. Another option is to find different colored butterfly bushes and plant them together to create a patchwork of colors during the blooming season.

Image credits (edits Gaspard Lorthiois):
CC BY 2.0: Smabs Sputzer, Andy Nunn
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