What soil does Giant hyssop grow in?

It tolerates these soils: average garden soil, sandy.

Is Giant hyssop hardy?

Hardy down to -23 °C (USDA zone 6, RHS H7). It gets through winter everywhere at lower altitudes, but may not survive unprotected in a mountain garden.

Is Giant hyssop toxic to children?

No. Reliable sources list it as non-toxic to children.

When does Giant hyssop flower?

Flowering: June–October, blue, purple, pink, orange, red, yellow, white.

How much water does Giant hyssop need?

Water need: medium. Drought tolerance: high.

How much does Giant hyssop cost?

It sells for roughly CZK 120 to CZK 280 in local shops, depending on size.

Giant hyssop

Agastache × hybrida

Giant hyssop (Agastache × hybrida) is a perennial. Light: full sun. Hardy down to -23 °C. Drought tolerance: high. Non-toxic to children. Sold in local shops from about CZK 120.

Illustration of Giant hyssop — An illustration of the typical shape of the mature plant, not a photo.

What it's good for, and what it isn't

An upright perennial with anise and mint scented leaves that carries dense flower spikes from midsummer to the frosts and is among the best plants for bees and butterflies. It needs full sun and sharply drained soil, because it stands winter wet far worse than cold. The blue and purple kinds (the anise hyssop and Korean mint relatives) are tougher and hardier, while the orange, pink and red southwestern types are short-lived and often die in wet winters; height (from knee-high dwarfs to chest height), flower colour and whether it self-seeds all vary by cultivar.

Watch out for

In Central Europe most plants are lost not to cold but to crown and root rot in heavy soil that stays wet in winter: plant in loose, gritty ground and leave the stems standing over winter for protection. The orange, pink and red flowered types often do not survive wet winters, and even the blue ones live only a few years, so expect to replace them now and then. Powdery mildew, rust and leaf spots occur, slugs can eat the spring shoots, and anise hyssop seeds itself around.

Key facts

Light: Full sun
Water need: Medium
Care: Medium
Size after 10 years: 80 cm × 50 cm
Hardiness: down to -23 °C
Foliage: Deciduous
Flowering: J F M A M J J A S O N D June–October, blue, purple, pink, orange, red, yellow, white

All details

Group	Perennial
Light	Full sun
Size after 10 years	80 cm × 50 cm
Ultimate size	0.3–1.2 m × 30–60 cm
Hardiness	down to -23 °C (USDA 6, RHS H7)
Soil	Average garden soil, Sandy
Foliage	Deciduous
Flowering	June–October, blue, purple, pink, orange, red, yellow, white
Water need	Medium
Drought tolerance	High
Maintenance	Medium
Root aggressiveness	Low
Suckering	no data
Spreading	Medium
Distance from buildings	no data
Distance from paving	no data
Litter	not typical
Planting distance	40 cm
For dogs	no data
For cats	no data
For children	Non-toxic
Typical price	from about CZK 120

Toxicity data is for information only. If your pet or child has eaten a plant, contact a vet or a doctor.

Sizes and prices available

The same plant is sold as a small pot and as a specimen several metres tall, and the price follows. Prices are rounded and for guidance only.

Size	Typical price
size not stated	approx. CZK 120 – CZK 280

Frequently asked questions

Data updated: October 17, 2026 · How our data is made

Appears in these lists

Perennials for full sun Perennials that flower all summer Drought-tolerant plants Drought-tolerant perennials Drought-tolerant plants for sandy soil Plants that are non-toxic to children Perennials for pollinators Plants for containers Plants for a Mediterranean garden Fragrant plants Fragrant perennials

Guide on the topic

A perennial border that flowers all summer: plants, layout, numbers A perennial border flowers from spring to autumn when its backbone is long-flowering perennials that bloom from June to September (catmint, woodland sage, coneflower, yarrow, Russian sage, gaura), with bulbs around them for spring and Japanese anemone, sedum and asters for autumn. Plant in groups of 3-7, tall at the back, low at the front; on average you need 5-7 plants per square metre. The calendars show the hardy perennials for a sunny spot that shops in your country sell most widely, with the price per plant.

Looks good next to it

Purple coneflower

Echinacea purpurea

Switchgrass

Panicum virgatum

Holly osmanthus

Osmanthus heterophyllus