Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. 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 it's a good idea to plant salpiglossis by looking at the USDA zone info.

Planting Calendar for Salpiglossis

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

Since salpiglossis require warm weather you really should wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant salpiglossis 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 salpiglossis and expect a good harvest is probably August. Any later than that and your salpiglossis may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your salpiglossis indoors.

Last Frost Date

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

Remember that USDA zone info for Rockville is an average and the actual date of last frost will vary from year to year. Half of the time in Rockville last frost occurs after April 15 so just be sure to be ready to protect your salpiglossis if you have a 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.