The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Roma should be read to figure out when it's a good idea to plant blue throatwort.

Planting Calendar for Blue Throatwort

Frost tolerance for blue throatwort:	Not tolerant of frost.
When to plant:	After the last frost.

You should not plant blue throatwort until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant blue throatwort in Roma 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 blue throatwort and expect a good harvest is probably September. Any later than that and your blue throatwort may not have a chance to fully mature. You can get started a little bit earlier by starting your blue throatwort indoors.

Last Frost Date

The average date of last frost is February 15 in Roma. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Roma is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Roma there is a last frost after February 15 be ready to cover your blue throatwort if you have a late frost.

USDA Zone Info for Roma

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Roma

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