Rainline Garden

When to plant rosemary in Gresham, OR

Plant young rosemary plants in Gresham Mar 15 – May 3.

Moderate Plant young plants

Why these dates

Gresham's typical last spring frost is March 16. As a cool-season crop that handles light frost, this crop doesn't need to wait for that date. In the west-side valleys, though, the soil usually isn't ready to work until about March 15.

West-side valleys. The Willamette Valley, Puget Sound and southern Oregon valleys. Long frost-free seasons, but soil stays cold and wet into May, so warm crops wait for warm soil, not just the last frost.

Difficulty
Moderate
Sun
Full sun
Spacing
24 to 36 inches apart
Planting depth
Plant at the depth it grew in the nursery pot
Frost
Handles light frost; wet winter soil is the bigger risk
First harvest
Pick sprigs a few weeks after planting, once new growth appears

Step by step

  1. Pick a sunny spot with soil that drains well, and mix in an inch or two of compost.
  2. Plant young rosemary plants Mar 15 – May 3, 24 to 36 inches apart. Plant at the depth it grew in the nursery pot.
  3. Water until established, then only in dry spells. In cold eastern areas, grow it in a pot and move it to a cool, bright spot for winter.
  4. Harvest: Snip sprig tips as needed. Don't cut back into bare wood; it won't regrow.

Varieties that do well here

  • Arp (selected for cold hardiness)
  • Hill Hardy
  • Tuscan Blue

Watch out for

Wet winter soil kills more rosemary than cold does. Plant in fast-draining soil or a raised bed.

Needs sharp drainage. It survives many west-side winters in a well-drained, sheltered spot; in colder eastern areas, grow it in a pot and bring it in for winter.

Common questions

When is the last frost in Gresham, OR?

Typically March 16. In 9 years out of 10, frost is over by April 12. These are 1991–2020 NOAA climate normals for Portland-Troutdale Airport.

Is it too late to plant rosemary in Gresham?

The spring planting window runs through May 3. Later plantings tend to struggle in summer heat.

How long until I can pick rosemary?

Pick sprigs a few weeks after planting, once new growth appears. Snip sprig tips as needed. Don't cut back into bare wood; it won't regrow.

Also plant in Gresham around the same time

Planting dates for rosemary in nearby areas

Full planting calendar for Gresham · Rosemary in every city