One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Mount Vernon can be read to estimate when to plant calliopsis.

Planting Calendar for Calliopsis

Frost tolerance for calliopsis:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Calliopsis are not cold tolerant which tells us that it's necessary to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant calliopsis in Mount Vernon 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. Any later than that and your calliopsis may not have a chance to grow to maturity. If you are starting your calliopsis indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Mount Vernon the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Mount Vernon 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 Mount Vernon you get surprised by a frost after April 15 be ready to cover your calliopsis if you have a surprise late frost.

USDA Zone Info for Mount Vernon

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 Mount Vernon

You may be interested in your other planting guides for Mount Vernon.