One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant tall phlox in Aspen should be estimated by using the USDA zone info.

Planting Calendar for Tall Phlox

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

Tall Phlox do well in some cold which tells us that you can plant them a little bit earlier in the year than other frost tender plants.

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

Last Frost Date

On average all chance of frost has passed is on April 15 in Aspen. In the coldest months of winter you should expect an average low temperature of -15°F.

Always keep in mind that USDA zone info for Aspen is not always accurate and the actual date of last frost is different every year. Since half of the time in Aspen you get surprised by a frost after April 15 be ready to cover your tall phlox if you have one of those late frosts.

USDA Zone Info for Aspen

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 Aspen

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