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When to Plant Thunbergia in Castle Rock, CO

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.

A common way of making a decision about when it's a good idea to plant thunbergia is to use the USDA zone info for Castle Rock.


Planting Calendar for Thunbergia

Frost tolerance for thunbergia: Not tolerant of frost.
When to plant: After all chance of frost has passed.

Thunbergia do not do well in cold weather which tells us that you have to wait until it warms up after all chance of frost has passed before you can plant them.

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

The earliest that you can plant thunbergia in Castle Rock is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant thunbergia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your thunbergia may not have a chance to really do well. If you are starting your thunbergia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Castle Rock may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Castle Rock last frost occurs after April 15 so make sure that you are prepared to cover your thunbergia if you have one of those late frosts.

USDA Zone Info for Castle Rock

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 Castle Rock

You may be interested in your other planting guides for Castle Rock.