The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By reviewing the USDA zone info for Romulus it's possible to determine when you can plant nierembergia.

Planting Calendar for Nierembergia

Frost tolerance for nierembergia:	Not tolerant of frost.
When to plant:	After the last frost.

It's not a good idea to plant nierembergia until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant nierembergia in Romulus is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant nierembergia and expect a good harvest is probably August. If you wait any later than that and your nierembergia may not have a chance to really do well. You can get started a couple of weeks earlier by starting your nierembergia indoors.

Last Frost Date

In Romulus the average date of last frost happens on April 15. It might get as low as -10°F during the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Romulus and it will vary from year to year. Since half of the time in Romulus you get surprised by a frost after April 15 be ready to protect your nierembergia if you have a surprise late frost.

USDA Zone Info for Romulus

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Romulus

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