When to Plant Calliopsis in Renton, WA

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.

The first chance to plant calliopsis in Renton should be determined by reviewing the USDA zone info.


Planting Calendar for Calliopsis

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

It's probably not a good idea to plant calliopsis until after all chance of frost has passed because they are not cold tolerant.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant calliopsis
Possibly ok, but a risky time to plant calliopsis
Probably not a good time to plant calliopsis

The earliest that you can plant calliopsis in Renton 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 calliopsis and expect a good harvest is probably August. You probably don't want to wait any later than that or else your calliopsis may not have a chance to fully mature. Starting your calliopsis indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on March 15 in Renton. You should expect an average low temperature of 15°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Renton and it can change quite a bit from year to year. Half of the time in Renton you get surprised by a frost after March 15 so always be ready to protect your calliopsis in the event of a surprise late frost.

USDA Zone Info for Renton

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 Low15°F
Highest Expected Low20°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 Renton

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