One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can figure out when it's a good idea to plant bidens in Lake Oswego by using the USDA zone info.

Planting Calendar for Bidens

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

Bidens require warm weather which means that you must wait until it warms up after the last frost before you can plant them.

The earliest that you can plant bidens in Lake Oswego 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 bidens and expect a good harvest is probably August. If you wait any later than that and your bidens may not have a chance to fully mature. You can get started a few weeks earlier by starting your bidens indoors.

Last Frost Date

On average all chance of frost has passed is on March 15 in Lake Oswego. In the coldest months of winter you can expect an average low temperature of 15°F.

Since the USDA zone info for Lake Oswego is just an average the actual date of last frost will vary from year to year. Half of the time in Lake Oswego it frosts late in the year after March 15 so always be ready to cover your bidens if you have a surprise late frost.

USDA Zone Info for Lake Oswego

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 Lake Oswego

You may be interested in your other planting guides for Lake Oswego.