When to Plant Hollyhocks in Denison, IA

One of the first steps you take when you are figuring out your gardening schedule is find your 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.

In Denison you can figure out when it's the best time to plant hollyhocks by checking out the USDA zone info.


Planting Calendar for Hollyhocks

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

Hollyhocks do ok in some cold which means that you can plant them just a bit earlier in the year than other frost tender plants.

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

The earliest that you can plant hollyhocks in Denison 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. If you wait any later than that and your hollyhocks may not have a chance to fully mature. If you are starting your hollyhocks indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Denison. In the coldest months of winter you can expect an average low temperature of -20°F.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Denison and it can change quite a bit from year to year. Since half of the time in Denison last frost occurs after April 15 be ready to protect your hollyhocks in the event of a late frost.

USDA Zone Info for Denison

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-20°F
Highest Expected Low-15°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 -15°F.

Plants to Grow in Denison

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