The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's a good idea to determine when it's the best time to plant bleeding hearts by using the USDA zone info for Boulder.

Planting Calendar for Bleeding Hearts

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

Bleeding Hearts are one of those plants that can tolerate a tiny bit of cold weather which means that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant bleeding hearts in Boulder 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 bleeding hearts and expect a good harvest is probably August. You probably don't want to wait any later than that or else your bleeding hearts may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your bleeding hearts indoors.

Last Frost Date

In Boulder the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Boulder is an average the actual date of last frost is different every year. Since half of the time in Boulder you get a frost after April 15 be ready to cover your bleeding hearts in the event of a late frost.

USDA Zone Info for Boulder

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 Boulder

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