When to Plant Xerianthemum in Thornton, CO

The USDA Zone info is a great tool for gardeners to help us estimate 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.

The best time to plant xerianthemum in Thornton should be figured out by checking out the USDA zone info.

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Planting Calendar for Xerianthemum

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

Since xerianthemum are barely cold tolerant you can plant them just a tiny bit earlier in the year than other frost tender plants.

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

The earliest that you can plant xerianthemum in Thornton 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 xerianthemum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your xerianthemum may not have a chance to fully mature. If you are starting your xerianthemum indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Thornton the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

Always keep in mind 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 Thornton and it can change quite a bit from year to year. Half of the time in Thornton you get surprised by a frost after April 15 so be sure to be ready to protect your xerianthemum in the event of a late frost.

USDA Zone Info for Thornton

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 Thornton

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