Getting it to bloom

Why won't my Blue Hair Grass bloom? (and how to make it flower)

Also called Blue hair grass, Glaucous hair grass, Large blue hair grass (Koeleria glauca).

More about blue hair grass

About Blue Hair Grass

Koeleria glauca · also called Blue hair grass, Glaucous hair grass · flowering

Koeleria glauca is a cool-season, clump-forming bunchgrass native to dry sandy and limestone grasslands of central Europe and central Asia, prized for its intensely blue-grey, fine-textured foliage and attractive silvery-green flower spikes in early summer. It is exceptionally tolerant of poor, alkaline, and sandy soils, and thrives in hot, dry conditions where richer soils would cause it to die out. The most important care fact is that it requires very sharp drainage and dislikes clay or fertile soils where it becomes short-lived. Not listed as toxic; considered pet-safe.

Plant type: flowering

The reasons blue hair grass isn't blooming

Almost every non-blooming blue hair grass 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 blue hair grass 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 blue hair grass to flower

Maximise sun. Give blue hair grass 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 blue hair grass and get the feeding right with the blue hair grass 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

Blue Hair Grass 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 blue hair grass care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Blue Hair Grass blooming — frequently asked questions

Why won't my blue hair grass flower?

Blue Hair Grass 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 blue hair grass bloom?

Give blue hair grass 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 blue hair grass normally bloom?