Getting it to bloom

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

Also called Mountain Phlox, Allegheny Phlox, Wideflower Phlox (Phlox ovata).

More about mountain phlox

About Mountain Phlox

Phlox ovata · also called Mountain Phlox, Allegheny Phlox · flowering

A low-growing Appalachian native perennial that forms spreading mats of ovate leaves studded with vivid pink to magenta flowers in mid-spring. Best suited to open woodlands, woodland edges, and partly shaded rocky slopes. It appreciates well-drained, slightly acidic soil with moderate moisture and is an excellent companion for spring bulbs and ferns.

Plant type: flowering

Watch for — Decline after flowering: Plants can look untidy after spring bloom. Shear lightly by one third after flowering to encourage fresh compact growth and reduce self-seeding.

The reasons mountain phlox isn't blooming

Almost every non-blooming mountain 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 mountain 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 mountain phlox to flower

Maximise sun. Give mountain 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 mountain phlox and get the feeding right with the mountain 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

Mountain 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 mountain phlox care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Mountain Phlox blooming — frequently asked questions

Why won't my mountain phlox flower?

Mountain 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 mountain phlox bloom?

Give mountain 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 mountain phlox normally bloom?