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

The USDA zone info for New Haven should be used to estimate when it's a good idea to plant cardinal flower.

Planting Calendar for Cardinal Flower

Frost tolerance for cardinal flower:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since cardinal flower require warm weather it's necessary to wait until after all chance of frost has passed before you can plant them.

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

Last Frost Date

On average all chance of frost has passed is on April 15 in New Haven. It might get as low as -10°F during the coldest months of winter.

Keep in mind that USDA zone info for New Haven may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in New Haven you get a frost after April 15 so always be ready to cover your cardinal flower in the event of a late frost.

USDA Zone Info for New Haven

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in New Haven

You may be interested in your other planting guides for New Haven.