Before planting it is a good idea to find your USDA Zone info to determine 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.

It's possible to estimate when to plant catharanthus by referring to the USDA zone info for Issaquah.

Planting Calendar for Catharanthus

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

Catharanthus require warm weather which tells us that you must wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant catharanthus in Issaquah 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 catharanthus and expect a good harvest is probably August. Any later than that and your catharanthus may not have a chance to fully mature. You can get started a little bit earlier by starting your catharanthus indoors.

Last Frost Date

The average date of last frost is March 15 in Issaquah. In the coldest months of winter you should expect an average low temperature of 15°F.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Issaquah and it changes from year to year. Since half of the time in Issaquah you get surprised by a frost after March 15 be ready to cover your catharanthus if you have a late frost.

USDA Zone Info for Issaquah

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Issaquah

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