Getting it to bloom

Why won't my Purple Needlegrass bloom? (and how to make it flower)

Also called purple needlegrass, purple stipa, nodding needlegrass (Nassella pulchra).

More about purple needlegrass

About Purple Needlegrass

Nassella pulchra · also called purple needlegrass, purple stipa · flowering

Nassella pulchra is the California state grass — a fine-textured, native bunchgrass producing narrow green to grey-green blades and delicate nodding purple-tinged flower spikes in spring. Perfectly adapted to dry California summers and wet winters, it is a cornerstone of native plant landscaping, wildlife gardens, and fire-resistant plantings in western North America.

Plant type: flowering

Watch for — Awn injury to pets and livestock: The sharp, spiralling awns on seed heads can penetrate pet fur and skin, causing painful injury. In pet gardens, mow or remove flower heads before seeds fully mature in late spring. This is a mechanical concern, not toxicity.

The reasons purple needlegrass isn't blooming

Almost every non-blooming purple needlegrass 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 purple needlegrass 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 purple needlegrass to flower

Maximise sun. Give purple needlegrass 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 purple needlegrass and get the feeding right with the purple needlegrass 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

Purple Needlegrass 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 purple needlegrass care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Purple Needlegrass blooming — frequently asked questions

Why won't my purple needlegrass flower?

Purple Needlegrass 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 purple needlegrass bloom?

Give purple needlegrass 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 purple needlegrass normally bloom?