How cold?

I confess to woeful ignorance regarding microclimates in the garden. Occasionally, I’ll glance to note areas where snow melts quickly, but with infrequent snowfall, these details are quickly forgotten. Of course, you should expect I’d know where the warm spots are after thirty-five years. But, as with many details in the garden, I am apparently too simple-minded to retain this vital information.

The moving water of the small pond below the sunroom did not freeze, and other parts of the garden will be watched to see where snow melts first.

Trees and shrubs sustained no damage from the snow, and most will tolerate much colder temperatures.

I recently purchased a laser thermometer to verify my guesses on where warm spots might be located. With more information, I could be encouraged to add more tender plants to the garden, but now I must wait for the snow to melt.

In any case, after an overnight drop to five degrees (Fahrenheit), no damage is apparent on grevillea (above) and fatsia (below) that are most marginal at that temperature. Snow was heaped to deeply cover one newly planted fatsia and two bromileads (Fascicularia bicolor) that were covered by the recent snow, but a bit more couldn’t hurt.

New plantings are less tolerant of cold than ones that are long established, but with several inches of snow over top, I’m not concerned at all. The curling of foliage of many broadleafed plants for protection returned to form as temperatures rose to near freezing in the afternoon.

With a load of four or five inches of snow, the grevillea leaned at a forty-five degree angle (above) the morning after. Brushing off the snow did no good, so the six foot tall shrub will be staked after the threat of snow has passed in March. Yes, it can snow in April, but what are the chances?

The biggest concern after what is likely to be our coldest night of winter (and the coldest in recent years) is possible damage to flowers of the paperbushes (Edgeworthia chrysantha, above). I recall damage at two or three degrees (above zero), and maybe scattered flower buds damaged at five degrees, but there was no damage a year ago at six degrees. Twice in years past, with temperatures several degrees and falling to seven below zero, paperbushes suffered damage to stems that required substantial pruning. Most likely, barely a flower will be lost from this freeze, but it will be a few weeks before I can tell for sure.