Agastache foeniculum Seeds | Snow Spike Anise Hyssop
LATIN NAME: Agastache foeniculum
COMMON NAME: Snow Spike Anise Hyssop
Plant Profile
Snow Spike is a white-flowered anise hyssop, with the same liquorice-scented foliage and upright habit as the species but spikes of clean white flowers instead of lavender-blue. Plants reach 90-120 cm, and the white heads show up in a border in a way that the blue ones cannot.
Flowering runs from July into September, and the spikes hold their shape as they fade, turning papery and pale. The foliage is mid-green, ovate and toothed, and it stays fresh until the first frost, which is longer than most tall perennials manage.
Anise hyssop is native to the northern prairies of North America, and the white form occurs in the wild as well as in cultivation. It is a plant of open ground and dryish soil, and it seeds freely where it is happy.
Science & Biotechnology
The white colour is a loss-of-function in the anthocyanin pathway rather than a different pigment, which is why the flowers have no trace of the blue in bud or in fade. The scent chemistry is unchanged: estragole dominates, with limonene and caryophyllene alongside.
Anise hyssop is one of the few Lamiaceae that is genuinely attractive to butterflies as well as bees, and its nectar is accessible to short-tongued insects because the florets are shallow. That is why a stand of it in July will hold more insect species than a comparable stand of lavender.
The genus name refers to the abundance of flowers, not to the herb hyssop, which is an unrelated plant. That confusion runs through older herbals and still appears in catalogues, where anise hyssop is sometimes listed as a hyssop for that reason alone.
Uses & Benefits
White flowers are useful where a border needs light rather than colour, and the plant works well with grasses, eryngiums and the grey-leaved artemisias. The spikes cut well and dry for winter work, and the leaves make an anise tea.
In the garden the plant is a pollinator stop at the height of summer, and its seed heads stand through winter. In North America anise hyssop is a recognised honey plant, and the white form is planted in apiaries for the same reason as the blue. In the kitchen the leaves are used sparingly, for tea and for flavouring fruit.
Growing from Seed
Sow on the surface at 18-21°C with light, and expect two to four weeks. Cold stratification for three weeks improves the result. The seedlings are slow at first and then grow strongly, so prick them out before they crowd.
Plant out at 40 cm apart in full sun, on ground that drains well. Water until established, then only in real drought. Cut the stems back in spring rather than autumn, and lift and divide every three years. The white form self-sows less vigorously than the blue, so leave a few heads to ripen if you want it to spread.
Our Take
The best white in a late-summer border that is otherwise all blue and yellow, and a plant that feeds insects for two months without any help.
Related Reading
Gardeners who grow Snow Spike Anise Hyssop often pair it with these related subjects: