One of the first steps you take when you are getting a good idea 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.

In Boulder you can figure out when you can plant pincushion flower by using the USDA zone info.

Planting Calendar for Pincushion Flower

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

Pincushion Flower do well in mild cold which means that you can plant them just a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant pincushion flower in Boulder is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant pincushion flower and expect a good harvest is probably September. If you wait any later than that and your pincushion flower may not have a chance to really do well. You can get started a few weeks earlier by starting your pincushion flower indoors.

Last Frost Date

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

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Boulder and it can change quite a bit from year to year. Half of the time in Boulder there is a last frost after April 15 so be sure to be ready to cover your pincushion flower in the event of one of those late frosts.

USDA Zone Info for Boulder

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 Boulder

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