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.

One way of figuring out when it's a good idea to plant hollyhocks is to examine the USDA zone info for Highland Park.

Planting Calendar for Hollyhocks

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

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

The earliest that you can plant hollyhocks in Highland Park 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 hollyhocks and expect a good harvest is probably September. You probably don't want to wait any later than that or else your hollyhocks may not have a chance to grow to maturity. Starting your hollyhocks indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Highland Park the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Highland Park is an average the actual date of last frost will vary from year to year. Since half of the time in Highland Park last frost occurs after April 15 be ready to protect your hollyhocks if you have one of those late frosts.

USDA Zone Info for Highland Park

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 Highland Park

You may be interested in your other planting guides for Highland Park.