The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of getting a good idea when it's possible to plant larkspur is to use the USDA zone info for Hillsboro.

Planting Calendar for Larkspur

Frost tolerance for larkspur:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Larkspur do ok in quite a bit of cold which tells us that you can plant them quite a bit earlier in the year than more sensitive plants.

The earliest that you can plant larkspur in Hillsboro is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant larkspur and expect a good harvest is probably September. You probably don't want to wait any later than that or else your larkspur may not have a chance to fully mature. If you are starting your larkspur indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Hillsboro. In the coldest months of winter you should expect an average low temperature of -10°F.

It's important to remember that USDA zone info for Hillsboro is not always accurate and the actual date of last frost changes from year to year. Half of the time in Hillsboro it frosts late in the year after April 15 so just be sure to be ready to cover your larkspur in the event of a surprise late frost.

USDA Zone Info for Hillsboro

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Hillsboro

You may be interested in your other planting guides for Hillsboro.