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

You can estimate when it's a good idea to plant verbena in Houston by reviewing the USDA zone info.

Planting Calendar for Verbena

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

Since verbena are one of those plants that can tolerate a tiny bit of cold weather you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant verbena in Houston 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 verbena and expect a good harvest is probably September. Any later than that and your verbena may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your verbena indoors.

Last Frost Date

On average the last frost is on February 15 in Houston. In the coldest months of winter you should expect an average low temperature of 20°F.

Keep in mind that USDA zone info for Houston is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Houston there is a last frost after February 15 be ready to protect your verbena if you have 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.