One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Portsmouth you can figure out when to plant xerianthemum by looking at the USDA zone info.

Planting Calendar for Xerianthemum

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

You can plant xerianthemum just a tiny bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant xerianthemum 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 xerianthemum and expect a good harvest is probably August. Any later than that and your xerianthemum may not have a chance to really do well. You can get started a couple of weeks earlier by starting your xerianthemum indoors.

Last Frost Date

The average date of last frost is April 15 in Portsmouth. You can expect an average low temperature of -10°F in the coldest months of winter.

Always keep in mind that USDA zone info for Portsmouth is an average and the actual date of last frost is different every year. Since half of the time in Portsmouth last frost occurs after April 15 be ready to cover your xerianthemum if you have one of those late frosts.

USDA Zone Info for Portsmouth

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 Portsmouth

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