One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Houston should be read to figure out when it's a good idea to plant columbine.

Planting Calendar for Columbine

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

You can plant columbine just a bit earlier in the year because they are moderately cold tolerant.

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

The last month that you can plant columbine and expect a good harvest is probably October. You probably don't want to wait any later than that or else your columbine may not have a chance to grow to maturity. If you are starting your columbine indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Houston the average date of last frost happens on February 15. You should expect an average low temperature of 20°F in the coldest months of winter.

It's important to remember that USDA zone info for Houston is an average and the actual date of last frost is different every year. Since half of the time in Houston you get a frost after February 15 be ready to cover your columbine in the event of a surprise late frost.

USDA Zone Info for Houston

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Houston

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