Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant hibiscus in Mercer Island should be estimated by checking out the USDA zone info.

Planting Calendar for Hibiscus

Frost tolerance for hibiscus:	Not tolerant of frost.
When to plant:	After the last frost.

It's a bad idea to plant hibiscus until after the last frost because they are not cold tolerant.

The earliest that you can plant hibiscus in Mercer Island is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant hibiscus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your hibiscus may not have a chance to really do well. If you are starting your hibiscus indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Mercer Island the average date of last frost happens on March 15. You can expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Mercer Island may not be accurate from year to year 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 hibiscus in the event of one of those late frosts.

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.