Getting it to bloom

Why won't my Silky Aster bloom? (and how to make it flower)

Also called Silky aster, Western silver aster, Silky prairie aster (Symphyotrichum sericeum).

More about silky aster

About Silky Aster

Symphyotrichum sericeum · also called Silky aster, Western silver aster · flowering

Symphyotrichum sericeum is a compact, drought-tolerant perennial native to dry rocky and sandy prairies across the central United States and southern Canada. It is distinguished by silvery-white silky hairs covering its stems and leaves, giving it a glittering appearance, and produces abundant 3–4 cm lavender to purple daisy-like flowers from late August to October. The most important care fact is excellent drainage: this species thrives in poor, lean, rocky or sandy soils and will decline or rot in rich, moist garden beds. Symphyotrichum sericeum is not listed as toxic to cats or dogs by the ASPCA.

Plant type: flowering

The reasons silky aster isn't blooming

Almost every non-blooming silky aster traces back to one of these, roughly in order of how common they are:

Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.
Too much nitrogen feed, driving lush foliage at the expense of flowers (very common with general or lawn feeds).
The plant has not been deadheaded, so it stops flowering once it sets seed.
Irregular watering — drought or waterlogging at the budding stage makes buds abort.
It is still too young or was checked by a transplant and is rebuilding before flowering.

Feeding silky aster a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.

The fix — how to get silky aster to flower

Maximise sun. Give silky aster the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers.
Switch the feed. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.
Deadhead regularly. Remove spent flowers often to keep it producing more rather than stopping to set seed.
Water consistently. Keep moisture even through budding and flowering — drought-then-flood swings make buds drop.

Light and feeding do most of the heavy lifting here. Dial in the spot with the light guide for silky aster and get the feeding right with the silky aster fertilising schedule — the wrong feed (too much nitrogen) is one of the most common silent reasons a healthy plant makes leaves instead of flowers.

Bloom season and what to expect

Silky Aster flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.

Post-bloom care so it flowers again

Deadhead, keep feeding lightly, and many will rebloom; collect seed from the best plants at the end of the season if you want to grow them again.

For everything else this plant needs day to day, see the full silky aster care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Silky Aster blooming — frequently asked questions

Why won't my silky aster flower?

Silky Aster blooms on the season's growth given enough sun, warmth and the right feed — there is no cold or photoperiod trick, just good growing conditions and a bloom-leaning feed. The most common reason it is not happening: Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.

How do I make silky aster bloom?

Give silky aster the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.

When does silky aster normally bloom?