One of the first steps you take when you are figuring out 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.

You will be able to determine when it's the best time to plant dipladenia by looking at the USDA zone info for Ottumwa.

Planting Calendar for Dipladenia

Frost tolerance for dipladenia:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's probably not a good idea to plant dipladenia until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant dipladenia in Ottumwa 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 dipladenia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your dipladenia may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your dipladenia indoors.

Last Frost Date

In Ottumwa the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°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 Ottumwa and it will vary from year to year. Half of the time in Ottumwa there is a last frost after April 15 so make sure that you are ready to cover your dipladenia if you have a surprise late frost.

USDA Zone Info for Ottumwa

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 Ottumwa

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