One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Westbrook you can estimate when it's the best time to plant helianthemum by referring to the USDA zone info.

Planting Calendar for Helianthemum

Frost tolerance for helianthemum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Helianthemum can survive in moderate cold which means that you can plant them a little earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant helianthemum in Westbrook is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant helianthemum and expect a good harvest is probably September. If you wait any later than that and your helianthemum may not have a chance to fully mature. If you are starting your helianthemum indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Westbrook. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Westbrook is an average the actual date of last frost will vary from year to year. Since half of the time in Westbrook you get surprised by a frost after April 15 be ready to cover your helianthemum if you have a late frost.

USDA Zone Info for Westbrook

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Westbrook

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