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 figuring out when it's a good idea to plant doronicum is to use the USDA zone info for Denver.

Planting Calendar for Doronicum

Frost tolerance for doronicum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant doronicum just a bit earlier in the year because they do well in moderate cold.

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

The last month that you can plant doronicum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your doronicum may not have a chance to fully mature. You can get started a little bit earlier by starting your doronicum 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.

Since the USDA zone info for Denver is not always accurate the actual date of last frost changes from year to year. Since half of the time in Denver you get surprised by a frost after April 15 be ready to cover your doronicum if you have one of those late frosts.

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.