When to Plant Iresene in Longmont, CO

The USDA Zone info is a great tool for gardeners to help us determine 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.

The best time to plant iresene in Longmont can be estimated by referring to the USDA zone info.


Planting Calendar for Iresene

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

Since iresene require warm weather it is important to wait until after the last frost before you can plant them.

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

The earliest that you can plant iresene in Longmont 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 iresene and expect a good harvest is probably August. If you wait any later than that and your iresene may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your iresene indoors.

Last Frost Date

The average date of last frost is April 15 in Longmont. You can expect an average low temperature of -15°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Longmont and it will vary from year to year. Half of the time in Longmont there is a last frost after April 15 so make sure that you are prepared to cover your iresene in the event of one of those late frosts.

USDA Zone Info for Longmont

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 Longmont

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