Getting it to bloom

Why won't my Douglas's Phlox bloom? (and how to make it flower)

Also called Douglas's phlox, Douglas phlox (Phlox douglasii).

More about douglas's phlox

About Douglas's Phlox

Phlox douglasii · also called Douglas's phlox, Douglas phlox · flowering

Phlox douglasii is a compact, mound-forming evergreen perennial native to rocky, subalpine slopes of western North America, from the Pacific Northwest to the Rocky Mountains. It produces a dense covering of small lavender-blue, pink, or white flowers in late spring to early summer, making it a prized choice for rock gardens and alpine troughs. Excellent drainage is the key requirement — the plant resents waterlogged soil at any time of year. No ASPCA listing found for this species; classified as mildly-toxic in the absence of confirmed safety data.

Plant type: flowering

Watch for — Powdery mildew: White, powdery coating on leaves in humid or shaded conditions; prune back after flowering to open up the canopy and improve airflow.

The reasons douglas's phlox isn't blooming

Almost every non-blooming douglas's phlox 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 douglas's phlox 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 douglas's phlox to flower

Maximise sun. Give douglas's phlox 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 douglas's phlox and get the feeding right with the douglas's phlox 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

Douglas's Phlox 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 douglas's phlox care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Douglas's Phlox blooming — frequently asked questions

Why won't my douglas's phlox flower?

Douglas's Phlox 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 douglas's phlox bloom?

Give douglas's phlox 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 douglas's phlox normally bloom?