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 hypericum is to examine the USDA zone info for Haverhill.

Planting Calendar for Hypericum

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

Since hypericum are barely cold tolerant you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant hypericum in Haverhill 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 hypericum and expect a good harvest is probably August. If you wait any later than that and your hypericum may not have a chance to really do well. Starting your hypericum indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Haverhill. In the coldest months of winter you should expect an average low temperature of -10°F.

Remember that USDA zone info for Haverhill is just an average and the actual date of last frost changes from year to year. Half of the time in Haverhill you get a frost after April 15 so make sure that you are ready to cover your hypericum if you have a late frost.

USDA Zone Info for Haverhill

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 Haverhill

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