When to Plant Lithospermum in Philadelphia, PA

One of the first steps you take when you are determining 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.

The earliest that you can plant lithospermum in Philadelphia can be estimated by referring to the USDA zone info.


Planting Calendar for Lithospermum

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

You can not plant lithospermum until after the last frost has passed because they require warm weather.

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

The earliest that you can plant lithospermum in Philadelphia 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 lithospermum and expect a good harvest is probably August. If you wait any later than that and your lithospermum may not have a chance to fully mature. If you are starting your lithospermum indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Philadelphia the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of 0°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Philadelphia and it can change quite a bit from year to year. Since half of the time in Philadelphia you get a frost after April 15 be ready to cover your lithospermum if you have a surprise late frost.

USDA Zone Info for Philadelphia

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low0°F
Highest Expected Low5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Philadelphia

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