Getting it to bloom

Why won't my Japanese astilbe bloom? (and how to make it flower)

Also called Japanese astilbe, Japanese false spirea (Astilbe japonica).

More about japanese astilbe

About Japanese astilbe

Astilbe japonica · also called Japanese astilbe, Japanese false spirea · flowering

Astilbe japonica is a species native to Japan, growing along stream banks and in moist mountain woodland. It produces elegant, narrow white to pale pink plumes in late spring to early summer — typically the earliest-blooming astilbe species. Its glossy, dark-green pinnate foliage is attractive even out of flower. Many early-season white astilbe cultivars, including 'Deutschland' and 'Rheinland', derive from this species.

Plant type: flowering

Watch for — Browning flower plumes: Early-blooming plumes are vulnerable to late frosts and drought. Cover plants with fleece if frost is forecast during budding. Maintain consistent soil moisture through flowering. Once brown, plumes will not recover but seed heads are ornamentally attractive.

The reasons japanese astilbe isn't blooming

Almost every non-blooming japanese astilbe 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 japanese astilbe 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 japanese astilbe to flower

Maximise sun. Give japanese astilbe 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 japanese astilbe and get the feeding right with the japanese astilbe 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

Japanese astilbe 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 japanese astilbe care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Japanese astilbe blooming — frequently asked questions

Why won't my japanese astilbe flower?

Japanese astilbe 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 japanese astilbe bloom?

Give japanese astilbe 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 japanese astilbe normally bloom?