Buddleja davidii 'Black Knight'

Spring - late · Outdoors

Feed with slow release fertiliser

Apply a general purpose slow release fertiliser, spreading it around the root area of the plant as it is coming into growth. (Or apply a liquid feed at regular intervals throughout the growing season.)

This is a simple way to provide a nutrient boost as a single annual procedure.

Spring-Autumn · Outdoors

Water during dry periods

For plants in the ground, when there has been little or no rain for a period of 7-10 days and the soil is dry, give it a deep watering and repeat weekly until there is a downpour of rain. Check plants in pots more frequently, especially in hot weather.

Spring - early · Planting

Prune hard to the base

Prune back to within 30cm to 45cm of the plant base so that the year's growth will begin from this low framework. If you want the plant to grow larger, this need only be done every few years.

Outdoor planting · Planting

Add root growth stimulant to the planting hole

Mycorrhizal fungi helps roots establish quickly, so they absorb water and nutrients more efficiently. It comes as a powder, granule or gel. Add to the planting hole or container, and to the plant's rootball before planting in the hole. For "bareroot" plants use a gel.

Planting

Deadhead blooms during flowering season

Remove flowers as they turn brown and fade. Snip the stem just below the bloom. This will keep the plant tidy and encourage more flowers.

The removal of spent flowers encourages the plant to produce fresh ones, rather than spend its energy on the development of seeds.