Dahlia 'Knockout'

Autumn - late · Outdoors

Apply a deep protective mulch

Provide a deep protective mulch in autumn, spreading it around the plant and covering it to give it both nutrients and some protection against the weather.

A mulch is a covering that can: protect the soil surface from rain, heat and cold; deter weeds; provide nutrients. Organic indicates that material has vegetative origin e.g. manure, compost. Synthetics i.e. plastics, or stones are often called mulches.

Autumn · Planting

Lift before winter

Lift bulbs. tubers or rhizomes in autumn, to keep for the following year. Keep dry and in a frost-free location for the winter. Re-plant in spring.

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-Autumn · Planting

Protect from slugs & snails

Protect young plants and new growth from slugs; mature plants can withstand slugs though damage affects their appearance. Apply nematodes in Spring. Or sprinkle organic slug pellets thinly around plants. Barrier methods, eg copper tape, may help.

Summer · Outdoors

Feed high potash

They benefit from a high potash feed as the flower buds develop unless the soil is in very good condition. This is more beneficial in container grown plants where soil nutrients can be exhausted.

Summer - early · Outdoors

Apply slow release fertiliser

Apply a slow release fertiliser which is spread around the root area of the plants soon after they have come 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.

Summer-Autumn · Planting

Support tall stems

The plant may require support for long stems. Provide an artificial frame which it can grow through, or loosely tie the whole plant. A network of twigs can be woven together to provide a framework through which the plant can grow.

Tall stems can lean or be battered by weather. Support the plant to keep its vertical lines, aiming for a natural appearance which is easy on the eye.

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.

Compost · Planting

Multi-purpose compost

Use a good quality peat-free multi-purpose compost when growing in pots and containers.