Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Silvis should be read to figure out when you can plant saxifraga.

Planting Calendar for Saxifraga

Frost tolerance for saxifraga:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant saxifraga just a tiny bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant saxifraga in Silvis 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 saxifraga and expect a good harvest is probably August. Any later than that and your saxifraga may not have a chance to fully mature. Starting your saxifraga indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Silvis. You should expect an average low temperature of -15°F in the coldest months of winter.

It's important to remember that USDA zone info for Silvis is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Silvis there is a last frost after April 15 so make sure that you are ready to cover your saxifraga if you have one of those late frosts.

USDA Zone Info for Silvis

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 Silvis

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