The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can estimate when it's a good idea to plant tall phlox in Onalaska by using the USDA zone info.

Planting Calendar for Tall Phlox

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

Since tall phlox do well in moderate cold you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant tall phlox in Onalaska 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 tall phlox and expect a good harvest is probably August. Any later than that and your tall phlox may not have a chance to grow to maturity. If you are starting your tall phlox indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Onalaska. In the coldest months of winter you should expect an average low temperature of -25°F.

Since the USDA zone info for Onalaska may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Onalaska there is a last frost after May 15 be ready to protect your tall phlox if you have a surprise late frost.

USDA Zone Info for Onalaska

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Onalaska

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