Flower · Asparagaceae
When to sow hostas
Grown for foliage, with the flowers a modest bonus. The standard answer to a shaded bed, and the standard casualty of slugs - thick blue-leaved cultivars resist them far better than thin yellow ones.
First worthwhile crop
Year 2
After planting, not after sowing.
Hardy in USDA zones
3a to 8b
Winter cold sets the limit here, not the calendar.
Frost tolerance
Very hardy
How much cold the plant itself will take.
Those weeks become real dates once you name a place.
Timing, in frost-relative terms
Nothing about a standing crop is sown to a calendar. Once planted, hostas stay in the ground for years, so the question is not when to sow but whether your winter is survivable and your planting window is open. Both answers come from your frost dates.
- Expect a first worthwhile crop in year 2 after planting.
- Hardy in USDA zones 3a–8b.
Getting the timing right
Plant while dormant in autumn or early spring, with the crown at soil level. Divide in early spring just as the shoots break the surface, when it is obvious where to cut. A hosta reaches its full size in year three and is unimpressive before then.
Frost tolerance
Hardy to -35C and completely dormant in winter, so cold is irrelevant to it. Needs a cold winter to break dormancy properly and performs poorly in frost-free climates. Emerging spring shoots are damaged by a hard late frost but recover.
Classified as very-hardy, with damage expected below -35°C (-31°F)-31°F (-35°C).