One of the first steps you take when you are making a decision about 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.

One way of determining when to plant xerianthemum is to consult the USDA zone info for Mercer Island.

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.

Xerianthemum 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 more sensitive plants.

The earliest that you can plant xerianthemum in Mercer Island 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. If you wait any later than that and your xerianthemum may not have a chance to fully mature. Starting your xerianthemum indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on March 15 in Mercer Island. It might get as low as 15°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Mercer Island is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Mercer Island you get a frost after March 15 be ready to protect your xerianthemum in the event of a late frost.

USDA Zone Info for Mercer Island

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Mercer Island

You may be interested in your other planting guides for Mercer Island.