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

The earliest that you can plant tall phlox in Monrovia should be figured out by referring to the USDA zone info.

Planting Calendar for Tall Phlox

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

Tall Phlox do well in moderate cold which tells us that you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant tall phlox in Monrovia is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant tall phlox and expect a good harvest is probably October. You probably don't want to wait any later than that or else your tall phlox may not have a chance to fully mature. If you are starting your tall phlox indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is January 31 in Monrovia. You should expect an average low temperature of 30°F in the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Monrovia and it will vary from year to year. Half of the time in Monrovia you get surprised by a frost after January 31 so make sure that you are prepared to cover your tall phlox in the event of a late frost.

USDA Zone Info for Monrovia

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Monrovia

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