One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

One way of estimating when it's the best time to plant delphinium is to look at the USDA zone info for Parker.

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 do well in very little cold which tells us that you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant delphinium in Parker 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. You can get started a little bit earlier by starting your delphinium indoors.

Last Frost Date

The average date of last frost is April 15 in Parker. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Parker is an average the actual date of last frost changes from year to year. Half of the time in Parker you get a frost after April 15 so make sure that you are prepared to protect your delphinium if you have a late frost.

USDA Zone Info for Parker

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 Parker

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