One of the first steps you take when you are figuring out 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 getting a good idea when it's a good idea to plant verbena is to use the USDA zone info for Portsmouth.

Planting Calendar for Verbena

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

Verbena are one of those plants that can tolerate a tiny bit of cold weather which means that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant verbena in Portsmouth 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 verbena and expect a good harvest is probably August. Any later than that and your verbena may not have a chance to fully mature. If you are starting your verbena indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Portsmouth the average date of last frost happens on March 15. In the coldest months of winter you should expect an average low temperature of 10°F.

Since the USDA zone info for Portsmouth is just an average the actual date of last frost is different every year. Half of the time in Portsmouth it frosts late in the year after March 15 so just be sure to be ready to protect your verbena in the event of a surprise late frost.

USDA Zone Info for Portsmouth

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Portsmouth

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