Agastache for Zone 4

12 of the 63 Agastache varieties in the Sow catalog are rated hardy through Zone 4, where winter lows reach -30°F to -20°F. Hardiness is per-variety, not per-genus — the plants listed above are the ones that hold up; others in the genus are not rated for this zone.

In Zone 4 the last spring frost typically lands around mid-May and the first fall frost around late September. Planting after the last frost — or in early fall, so roots establish before the ground cools — gives the best establishment. Each plant page lists its own planting months.

Start at the top of the list above: it is ranked by how many gardeners actually save and grow each variety, which is a strong real-world reliability signal. Then narrow by your sun exposure and the mature size that fits the bed.