I live in an area that does not get below freezing too often, but is very consistent between 32-45 deg in the winter. I am wondering what the impact is on trees that are good with low chill areas in this area, even if they can withstand frost? Do trees that need a higher number of chill hours (600-800) grow better? Obviously, it would need to cross the varietal's threshold for preferable growth. Though many nurseries advertise the chill hours needed, I haven't come across anything that indicates a ceiling to the hours. Any thoughts?
The thing about planting things with chill hours that are far less than your area gets is that as after they achieve those hours they can start spring activities (bud growth, flowering) at the next warm spell. This is fine if your area won't have anymore freezing weather, but the tree is vulnerable to winter weather in a way that it wouldn't be if it were still dormant.
Location: Atascadero, CA 9a
posted 2 years ago
Good point. Thinking if necessary mix in a little of both. Put some low chill hr items near structures and keep the others in the more open areas.
Chill hours are roughly the number of hours between the temperatures of 32-45 degrees f.
Winter hours above 60 degrees are subtracted from the totals.
The idea is that a deciduous plant goes dormant in the cold winter to protect itself from the cold.
The USDA zone tells you the coldest temperatures in your area.
Broadly speaking, the chill hours tell you how long the cold temperatures last.
Luckily, there are institutions already tracking this information for you.
Contact a Master Gardener in your area or call the state plant board.
If a tree doesn’t experience enough chill hours in the winter the flower buds might not open at all in spring, or they might open unevenly.
In addition, the production of leaves may also be delayed.
A low-chill tree in a high-chill area would break dormancy too soon and be damaged, or even killed, by the cold weather.