Mature size & growth rate

How big does Hummingbird Mint (Agastache rupestris) get?

Also called sunset hyssop, hummingbird mint, rock anise hyssop.

More about hummingbird mint

About Hummingbird Mint

Agastache rupestris · also called sunset hyssop, hummingbird mint · herb

Agastache rupestris, sunset hyssop, is an aromatic Southwest US native with fine, threadlike grey-green leaves and slender spikes of smoky-orange flowers with lavender calyces from summer into autumn. Smelling of root beer and mint, it thrives in full sun and sharp drainage, tolerates heat and drought, and draws hummingbirds and bees.

Mature size: About 60-90 cm tall and 30-45 cm wide (2-3 ft by 1-1.5 ft).

Indoor size vs how big it gets in the wild

Hummingbird Mint stays fairly low but widens over time — it spreads into a bigger clump by offsets, runners or rhizomes rather than shooting upward. Indoors and in a pot, expect about 60-90 cm tall and 30-45 cm wide (2-3 ft by 1-1.5 ft).. A pot, your light levels and a little pruning are what set the final size in a home, far more than the plant's theoretical potential.

Size here is about width, not height: the plant builds an ever-wider clump or sends out plantlets and runners while staying relatively short.

Growth rate and years to mature

Hummingbird Mint is a fast grower. Realistically, expect two to four years from a young plant to a room-filling specimen in good light. Its feeding profile backs this up: very low feeder; lean soil gives the best results. skip rich fertiliser, which causes soft, floppy, short-lived growth. a light spring grit or compost top-dressing is all it needs.

Want this turned into the right next pot at the right moment? The pot size calculator and the hummingbird mint repotting guide cover when and how much to size up — pot size is one of the biggest levers on how fast hummingbird mint grows.

How to keep hummingbird mint smaller

You are not stuck with the maximum size. For hummingbird mint specifically, these are the levers, in order of impact:

Divide the clump every year or two — splitting hummingbird mint is the main way to control its spread and refresh it.
Remove runners, plantlets or offsets as they appear if you want it to stay a single tight clump.
Keep it slightly pot-bound; a snug pot naturally limits how wide the clump can get.

The keep-it-smaller method, step by step

Lift the whole plant. Slide hummingbird mint out of its pot in spring when the clump has filled it.
Split the clump. Tease or cut the rootball into two or more sections, each with healthy roots and growth.
Repot one division. Put a single division back in the original pot to reset it to a smaller size; pot or give away the rest.
Remove offsets as they form. Through the year, detach new runners or pups to stop it spreading again.

How to grow hummingbird mint bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for hummingbird mint the accelerators are:

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger.
Good light plus regular feeding maximises offset and runner production.
Leave plantlets and offsets attached and feed through the growing season for the fastest spread.

Light is almost always the ceiling. The hummingbird mint light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When hummingbird mint outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for hummingbird mint:

The clump bulging over the pot rim or splitting the pot — the cue to divide, not to find a bigger room.
A dense centre that goes bare or tired while the edges keep spreading.
Runners or offsets escaping across the shelf or into neighbouring pots.

If it is the pot rather than the room, it is a repotting job, not a goodbye — see the hummingbird mint repotting guide. If you want more of this plant instead of a bigger one, the hummingbird mint propagation guide turns prunings into new plants.

Hummingbird Mint size — frequently asked questions

How big does hummingbird mint get?

Hummingbird Mint reaches about 60-90 cm tall and 30-45 cm wide (2-3 ft by 1-1.5 ft). when grown indoors. Size here is about width, not height: the plant builds an ever-wider clump or sends out plantlets and runners while staying relatively short.

Is hummingbird mint slow or fast growing?

Hummingbird Mint is a fast grower. Expect two to four years from a young plant to a room-filling specimen in good light. Hummingbird Mint stays fairly low but widens over time — it spreads into a bigger clump by offsets, runners or rhizomes rather than shooting upward.

How long does hummingbird mint take to reach full size?

Roughly two to four years from a young plant to a room-filling specimen in good light. Light, pot size and feeding move that timeline more than anything else.

How do I keep hummingbird mint smaller?

Divide the clump every year or two — splitting hummingbird mint is the main way to control its spread and refresh it. Remove runners, plantlets or offsets as they appear if you want it to stay a single tight clump. Keep it slightly pot-bound; a snug pot naturally limits how wide the clump can get.

How can I make hummingbird mint grow bigger or faster?

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger. Good light plus regular feeding maximises offset and runner production. Leave plantlets and offsets attached and feed through the growing season for the fastest spread.