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When to Plant Penstemon in Westminster, CO

One of the best tools that you have as gardeners to help us determine 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.

The USDA zone info for Westminster should be reviewed to figure out when you can plant penstemon.


Planting Calendar for Penstemon

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

Penstemon tend to make it in mild cold which tells us that you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant penstemon
Possibly ok, but a risky time to plant penstemon
Probably not a good time to plant penstemon

The earliest that you can plant penstemon in Westminster 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 penstemon and expect a good harvest is probably September. You probably don't want to wait any later than that or else your penstemon may not have a chance to grow to maturity. Starting your penstemon indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Westminster and it can change quite a bit from year to year. Since half of the time in Westminster you get surprised by a frost after April 15 be ready to cover your penstemon in the event of a late frost.

USDA Zone Info for Westminster

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 Westminster

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