Getting it to bloom

Why won't my Veronicastrum virginicum bloom? (and how to make it flower)

Also called Culver's root, blackroot (Veronicastrum virginicum).

More about veronicastrum virginicum

About Veronicastrum virginicum

Veronicastrum virginicum · also called Culver's root, blackroot · flowering

Veronicastrum virginicum is a stately North American prairie perennial sending up tall, erect stems topped with slender, tapering spires of white to pale-lilac flowers in mid to late summer. Its whorled foliage and architectural candelabra form suit naturalistic and prairie-style borders, and the nectar-rich spikes are magnets for bees and other pollinators.

Plant type: flowering

Watch for — Slow to establish: Plants can take a season or two to bulk up and flower well; be patient and avoid disturbing young clumps.

The reasons veronicastrum virginicum isn't blooming

Almost every non-blooming veronicastrum virginicum 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 veronicastrum virginicum 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 veronicastrum virginicum to flower

Maximise sun. Give veronicastrum virginicum 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 veronicastrum virginicum and get the feeding right with the veronicastrum virginicum 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

Veronicastrum virginicum 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 veronicastrum virginicum care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Veronicastrum virginicum blooming — frequently asked questions

Why won't my veronicastrum virginicum flower?

Veronicastrum virginicum 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 veronicastrum virginicum bloom?

Give veronicastrum virginicum 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 veronicastrum virginicum normally bloom?