Before planting it is a good idea to find your USDA Zone info to estimate 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.

In Roanoke you can estimate when to plant delphinium by reviewing the USDA zone info.

Planting Calendar for Delphinium

Frost tolerance for delphinium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Delphinium are barely cold tolerant which means that you can start planting them slightly earlier than more sensitive plants.

The earliest that you can plant delphinium in Roanoke is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant delphinium and expect a good harvest is probably August. If you wait any later than that and your delphinium may not have a chance to fully mature. Starting your delphinium indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Roanoke. It might get as low as 5°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Roanoke is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Roanoke there is a last frost after April 15 be ready to cover your delphinium if you have a late frost.

USDA Zone Info for Roanoke

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Roanoke

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