One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of making a decision about when it's a good idea to plant purple bell vines is to consult the USDA zone info for Walla Walla.

Planting Calendar for Purple Bell Vines

Frost tolerance for purple bell vines:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since purple bell vines are one of those plants that can tolerate a tiny bit of cold weather you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant purple bell vines in Walla Walla is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant purple bell vines and expect a good harvest is probably August. Any later than that and your purple bell vines may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your purple bell vines indoors.

Last Frost Date

The average date of last frost is April 15 in Walla Walla. You can expect an average low temperature of 0°F in the coldest months of winter.

Remember that USDA zone info for Walla Walla may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Walla Walla there is a last frost after April 15 so always be ready to cover your purple bell vines in the event of one of those late frosts.

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.