Warm sites fight off cold temperatures
: I live in Anthem and, according to my car temperature gauge, it seems to run several degrees cooler at my home. I have been babying a Mexican lime for a year now, after having lost one and a Meyer lemon two winters ago. Could you suggest where and how I might have a Meyer lemon?
A: The safest information out there is from Sunset. It is better than Department of Agriculture and information from the National Arboretum. Pockets of more protected climates exist all through the valley. Nurseries get reports from people that a Mexican lime will grow here, but they do not know what microclimate it is grown in and how it is grown.
To be on the safe side, do not grow anything that cannot withstand freezing temperatures. But what a boring landscape that would be to the adventurous gardener! So you would need to experiment, keeping the following in mind. When growing cold-sensitive plants outside look for the following for warmer locations:
In the valley
* Lower elevation but not the lowest elevation or the bottom of the valley. Air gets colder with increasing elevation. Coldest air settles in the lowest geographical pockets of the valley.
* Lots of pavement or concrete buildings that help radiate heat at night.
* Lack of wind, which removes warm air and replaces it with colder air that lowers temperatures faster and results in freezes that last longer.
In the yard
* South- and west-facing orientation of the landscape is warmer than east- and north-facing orientations.
* Rock mulch is warmer than grass or plant-covered landscapes.
* Tree canopies capture radiated heat from the landscape so temperatures can be a bit warmer under tree canopies.
* Water in the landscape tends to make the area around the water warmer.
* This may be all negated if you do not control wind. Use windbreaks and plant covers to trap heat in the landscape. This may contribute as much as 5 to 6 F.
Mexican lime will not handle temperatures below freezing. Meyer lemon will handle temperatures down to the low 20s unless it is grafted on to a rootstock that will not handle freezing temperatures.
It might be best for you to stay away from tender plants and refer to your Sunset book for freeze tolerance and use its planting zones to be on the safe side.
Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by e-mail at morrisr@unce.unr.edu.