One of the first steps you take when you are making a decision about 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.

By referring to the USDA zone info for Leander you should be able to determine when it's possible to plant cosmos.

Planting Calendar for Cosmos

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

Since cosmos do ok in moderate cold you can plant them just a tiny bit earlier in the year than more sensitive plants.

The earliest that you can plant cosmos in Leander 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 cosmos and expect a good harvest is probably August. If you wait any later than that and your cosmos may not have a chance to fully mature. You can get started a few weeks earlier by starting your cosmos indoors.

Last Frost Date

The average date of last frost is March 15 in Leander. In the coldest months of winter you should expect an average low temperature of 15°F.

Since the USDA zone info for Leander is just an average the actual date of last frost will vary from year to year. Since half of the time in Leander you get a frost after March 15 be ready to cover your cosmos in the event of one of those late frosts.

USDA Zone Info for Leander

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Leander

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