Buddleja, Buddleja, or butterfly bush is one of the most fragrant garden plants (and indeed, seeing it full of butterflies is a great gardening experience).
Growing Butterfly Bush
This Chinese native is hardy into USDA zone 5 (4 with deep mulch) but dies to the ground in this zone. It does perform much better in warmer gardens than this as it has demonstrated a tendency to self-sow and become a nuisance-invasive plant.
In these warmer areas of zone 7, the butterfly bush can become a large shrub between 5-10 feet tall. In colder zones, it is not unusual to see it grow 5 feet in a single year before blossoming before being killed to the ground by winter.
Buddleja has a straggly growth habit – and those in warm climates who have an ugly-looking plant can cut it to the ground to renovate it. The plant blooms on new wood, so heavy pruning will not reduce the number of blooms.
It is a good thing those flowers are extremely fragrant as otherwise, butterfly bush wouldn’t be included in a good garden. It has no fall coloring to speak of, although the leaves stay on the plant for a long time into the fall.
But the flowers! They range in length from 4-10 inches, and while the most common color is lilac-purple, there are others in the pinks, reds, whites, and shades of purplish-violet.
And these flowers are extremely fragrant while blooming from late summer to heavy frost.
Deadhead regularly to increase the number of blooms.
The seeds are carried in small fruit which has no ornamental value (too tiny).
Butterfly bush grows best in full sun and fertile soils. You’ll get the heaviest bloom there, and shade will simply reduce the growth and flowers. I put a plant into the medium shade one summer to try it there, and it languished all summer throwing spindly shoots.
Suppose you want to make a statement in the summer garden, plant buddleia in clumps. One plant alone can be ugly unless it is in bloom, but a clump of three looks like a spreading shrub.
One solution is to treat the butterfly bush as an herbaceous perennial (I do) in the middle to back of the border and cut it to the ground in the fall along with the rest of the plants.
Growing Buddleia from seed
The seed starts readily and easily with a soil temperature of 70F, and a small plant started in January will give a small bloom the first year in the fall (if grown in fertile soils). Named plants can be easily started using regular tender tip cuttings.
Once the cuttings have rooted, transplant into larger pots and do not overwater; they have a tendency to rot quickly if overwatered.
Commonly available varieties include:
var. nanhoensis – Compact form (4′-8′ tall). Hybrids include ‘Nanho Alba,’ ‘Nanho Blue,’ and ‘Nanho Purple,’ ‘Black Knight’ has dark purple flowers and is slightly more cold hardy than the species.
‘Dartmoor’ – branched flowers with magenta/purple blooms. It can be a big plant.
‘Empire Blue’ – Flowers violet-blue with an orange eye. Upright growth.
‘Fascination’ – Lilac-pink flowers on large panicles 13″ to 18″ long. Vigorous
‘Harlequin’ – White and green variegated foliage with reddish-purple flowers. Not a vigorous grower.
‘Honeycomb’ – An extremely popular yellow-flowering hybrid butterfly bush
‘Lochinch’ – A silvery leaf compact plant. The flowers are lavender with an orange eye and are in smaller clusters (5″-6″ long) than normal.
‘Royal Red’ – The best red-flowered form. Flowers up to 20″ long.
‘White Profusion’ – White flowers, but flowers only 6″ to 8″ long.
Buddleja Davidii – Pink
There were already two magnificent deep pink cultivars before cultivars like ‘Sugar Plum’ and ‘Miss Ruby’ expanded the palette of Buddleja colors – yet both had problems. ‘Pink Spread’ has lovely pink-red blooms and a horrible, thin, spreading growth habit; worse, it doesn’t renew effectively from the base, leaving a considerable amount of the old wood showing.
‘‘Summer Beauty is a lovely plant with brilliant cerise-pink blooms, but it’s difficult to propagate and grow, and the blossoms sometimes fade to mauve color.
Given the drawbacks of both ‘Pink Spread’ and ‘Summer Beauty,’ it may be a mistake to utilize them to produce new cultivars. All of the ‘Summer Beauty’ seedlings I’ve grown have ended up in the compost heap. On the other hand, a few ‘Pink Spread’ offspring have performed admirably.
Because the one pictured is a result of a cross with ‘Summer Beauty,’ it might have inherited both of their undesirable behaviors. All of its siblings had been rejected. This one jumped out since it had a nice color and a significant growth habit.
The blooms have a reddish-pink color that fades to a mosaic of brighter and deeper colors. The panicle is very big and open. It spreads quickly and has a moderate amount of vigor without becoming uncontrolled.
It isn’t ideal yet, in my opinion. It’s still a work in progress, and I’m seeking a good partner to help me develop the next iteration.
Buddleja alternifolia is a bushy, deciduous shrub with a spreading habit that grows quickly.
It is frequently trimmed to a single trunk to emphasize the beautiful arching stems that give the plant a weeping appearance, although it may still be a magnificent bushy shrub.
Small clusters of fragrant lilac-purple tubular blooms cover the stalks in the summer. The clusters can grow so thick that the stems are entirely encircled.
It prefers to be in the sun, although it will tolerate moderate shade. However, it will produce fewer blooms and seem less dense in the shadow.
Use in borders to create the sense of a country garden.
Soil: Soils with good drainage.
Once blooming is completed, prune the plant once a year. Remove any old branches from the base and trim the flower shoots to just above some fresh growth. Don’t go overboard; simply remove around 25% of the old stems.