Overview
Buddleia (also known as Buddleija and, Butterfly bush) are very easy to grow either from seed, cuttings, or small shrubs, but once established some varieties will grow to be quite tall (about 10 feet or 3 meters), so you will need somewhere spacious with plenty of sunshine, and if possible some protection from the wind.
The most important growing condition for Buddleia is well draining soil, this is essential, so when choosing a spot for your Buddleia make sure the water drains freely through the soil, if it doesn't, either find another spot or dig over the soil putting in plenty of organic material and gardening sand to raise the level of the soil.
Buddleia grow best in an average to fertile soil with a neutral to slightly acid pH (if you haven't got a pH meter, don't worry, as long as the Buddleia has got good drainage and sunlight it will probably be happy)
Growing Buddleia from Seed
You will need:
- Some loam based compost
- Clean seed trays
- A small amount of fine light coloured sand
- Peat pots
Step 1
Fill the seed tray with the loam based compost and let it stand in about 1 inch (2.5cm) of water for fifteen minutes until the compost is soaked through to the surface. Remove the seed tray and let it stand on a free draining surface for half an hour.
Step 2
While you are doing the above, mix the Buddleia seed with the fine light coloured sand. You only need about half a handful of sand.
Step 3
Sprinkle the surface of the compost with the sand/seed mix, trying to cover the surface as evenly as possible. Gently tap the sand/seed mix down using the base of another seed tray or something of equal proportions. Do not cover the seeds with compost.
Step 4
Place the tray in a light sunny position indoors (a sunny window sill for example) and spray as needed with a fine water sprayer to keep the compost damp. The seeds should germinate in about three weeks.
Step 5
When the seedlings have four proper leaves prick them out of the compost and in to the peat pots (one per pot) Keep the compost damp, remember that Buddleia like free draining soil.
Step 6
Plant out in late spring/early summer, when there have been no more frosts plant the young shrubs in the garden. Remember that they need well drained soil, plenty of space to grow, and plenty of sunshine. Dig holes of at least 6 inches (15 cm) deep and put the plants in, still in the peat pots making sure that the soil covers the top of the peat pot.
How to prune Buddleia
To ensure a healthy plant for the next season it's important to prune back the bush to about 2 ft (0.6 m) tall, leaving two or three buds above the base. Late winter or early spring is the best time to carry this out. This sounds drastic and it creates quite a pile of branches to dispose of, but it is essential work. Also, to encourage reflowering, remove old flowers as and when needed, this will encourage new flowers and make for an even more spectacular sight and it will flower well into autumn.
Buddleia davidii - Butterfly Bush (Loganiaceae)
Family: Loganiaceae. hardly any diseases or pests of any great significance
Plant Category: shrubs.
Tolerances: drought, deer, heat & humidity, pollution, rabbits, seashore, but must have free draining soil.
Light Range: Sun to Full Sun
pH Range: 5.5 to 6.5
Soil Range: Mostly Sand to Some Clay
Water Range: Semi-Arid to Moist
Bloomtime Range: Early Summer to Mid Autumn
US Hardiness Zones 5-10. Buddleia will die to the ground in winter in zones 5 and 6 but it comes back in spring.
Britain and Ireland Hardiness Zones:
Hardiness zones relevant to Britain and Ireland are fairly high, from 7 to 10, and are not a problem for Buddleia.
7. In Scotland the Grampians, Highlands and locally in the Southern Uplands, in England the Pennines and in Wales the highest part of Snowdonia.
8. Most of England, Wales and Scotland, and parts of central Ireland.
9. Most of western and southern England and Wales, western Scotland, also a very narrow coastal fringe on the east coast of Scotland and northeast England (within 5 km of the North Sea), London, and most of Ireland.
10. Very low lying coastal areas of the southwest of Ireland and the Isles of Scilly.
(In other words Buddleia should grow well in any part of the UK.)