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.

One way of estimating when it's possible to plant alyssum is to consult the USDA zone info for Walla Walla.

Planting Calendar for Alyssum

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

Alyssum can survive in pretty solid cold which means that you can plant them quite a bit earlier in the year than more sensitive plants.

The earliest that you can plant alyssum in Walla Walla 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 alyssum and expect a good harvest is probably September. If you wait any later than that and your alyssum may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your alyssum indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Walla Walla. In the coldest months of winter you can expect an average low temperature of 0°F.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Walla Walla and it can change quite a bit from year to year. Since half of the time in Walla Walla it frosts late in the year after April 15 be ready to protect your alyssum if you have a late frost.

USDA Zone Info for Walla Walla

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Walla Walla

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