Before planting it is a good idea to find your USDA Zone info to determine 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 Denver you can estimate when you can plant blue throatwort by referring to the USDA zone info.

Planting Calendar for Blue Throatwort

Frost tolerance for blue throatwort:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Blue Throatwort require warm weather which tells us that you really should wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant blue throatwort in Denver 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 blue throatwort and expect a good harvest is probably August. Any later than that and your blue throatwort may not have a chance to really do well. You can get started a couple of weeks earlier by starting your blue throatwort indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Denver. It might get as low as -15°F during the coldest months of winter.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Denver and it will vary from year to year. Half of the time in Denver last frost occurs after April 15 so make sure that you are prepared to protect your blue throatwort if you have a surprise late frost.

USDA Zone Info for Denver

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 Denver

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