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 Rockville you can determine when to plant canna by using the USDA zone info.

Planting Calendar for Canna

Frost tolerance for canna:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's a bad idea to plant canna until after the last frost has passed because they require warm weather.

The earliest that you can plant canna in Rockville 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 canna and expect a good harvest is probably August. Any later than that and your canna may not have a chance to fully mature. If you are starting your canna indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Rockville. You should expect an average low temperature of 0°F in the coldest months of winter.

Since the USDA zone info for Rockville is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Rockville last frost occurs after April 15 be ready to cover your canna if you have a surprise late frost.

USDA Zone Info for Rockville

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Rockville

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