Getting it to bloom

Why won't my Agastache 'Black Adder' bloom? (and how to make it flower)

Also called Black Adder agastache (Agastache 'Black Adder').

More about agastache 'black adder'

About Agastache 'Black Adder'

Agastache 'Black Adder' · also called Black Adder agastache · flowering

Agastache 'Black Adder' is an aromatic hybrid hyssop with dense, smoky violet-blue flower spikes emerging from near-black buds from midsummer to autumn. Vigorous and long-blooming, it wants full sun and free-draining soil, tolerates heat and drought once established, and is a prolific nectar source for bees, butterflies and hummingbirds.

Plant type: flowering

The reasons agastache 'black adder' isn't blooming

Almost every non-blooming agastache 'black adder' 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 agastache 'black adder' 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 agastache 'black adder' to flower

Maximise sun. Give agastache 'black adder' 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 agastache 'black adder' and get the feeding right with the agastache 'black adder' 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

Agastache 'Black Adder' 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 agastache 'black adder' care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Agastache 'Black Adder' blooming — frequently asked questions

Why won't my agastache 'black adder' flower?

Agastache 'Black Adder' 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 agastache 'black adder' bloom?

Give agastache 'black adder' 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 agastache 'black adder' normally bloom?