How to plant and grow asters

Asters are brilliant for the autumn garden, and the insects love them, laden with pollen and nectar.

Planting

Soil and Site

Full sun to partial sun. Soil should be moist, well-drained, and average to humus-rich. All Aster amellus varieties are drought-tolerant and perform in well-drained soil.

Spacing

40cm (16in)

In the garden

Pinch in midsummer to encourage a longer flowering season.

For containers

Asters can be grown in containers in well-drained compost.. The plants should be cut back after flowering and then, if possible, stored in pots in a cold frame or greenhouse over the winter. Keep the pots moist but not sodden, and do not apply extra heat. 

When there is the first sign of new growth in spring, remove the plants from their containers and repot in fresh compost. This is the time to divide them if they are large enough. Once repotted, do not put back them under cover, but slowly harden them off and do not let them dry out.

Aftercare

Cut down after flowering.

Most Asters will need dividing every fourth year to maintain vigour. All asters are best divided in spring as new growth starts. Lift the clump and then use two back-to-back forks to split it. Take care of old stems, they can be sharp. Some varieties are denser and may need a knife or spade to cut through. Discard old woody pieces and use newer sections from the outside of the clump. Add grit to the base of the hole on heavy ground. Water until established.

Cut Flowers

They will look good for a fortnight. If you strip all the leaves below the water line and thin out the leaves up the stem a bit more, and put a drop of bleach in the water, it will maximise the cut-flower potential.