Getting it to bloom

Why won't my White mountain heather bloom? (and how to make it flower)

Also called White mountain heather, Western moss heather, Mertens' cassiope (Cassiope mertensiana).

More about white mountain heather

About White mountain heather

Cassiope mertensiana · also called White mountain heather, Western moss heather · flowering

White mountain heather is a low-growing alpine subshrub native to western North America, from Alaska to California, found at high elevations near snowfields. Its four-ranked scale-like leaves clothe wiry stems, and it produces delicate white bell flowers on red stalks in early summer. An ideal plant for cool, acidic rock gardens.

Plant type: flowering

The reasons white mountain heather isn't blooming

Almost every non-blooming white mountain heather 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 white mountain heather 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 white mountain heather to flower

Maximise sun. Give white mountain heather 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 white mountain heather and get the feeding right with the white mountain heather 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

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

White mountain heather blooming — frequently asked questions

Why won't my white mountain heather flower?

White mountain heather 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 white mountain heather bloom?

Give white mountain heather 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 white mountain heather normally bloom?