UNITED STATES—This does not seem like such a mild climate when it is difficult to distinguish between the time and the temperature on a local bank clock tower. You know; when punctuation is the only difference between four minutes past one, and one hundred four degrees. Fortunately, like mild frost in winter, hot weather does not happen too often, which is why this climate really is milder than most.
Most of us know what to do for the garden when the weather gets warmer. Obviously, many plants want more water. What we do not often consider is that there a few things that we should ‘not’ do. Unlike us, the plants in the garden cannot find shade when the weather gets warm. Those that are exposed find creative ways to provide their own shade. We really do not want to mess with that.
By this time of year, outer foliage of exposed plants is mature enough to tolerate heat. Only foliage of plants that prefer to be partly shaded is likely to be damaged. However, inner foliage of even the toughest plants is not as resilient as outer foliage is. Simply shearing a hedge exposes inner foliage that can be scorched by overexposure. Sunlight enhances the effects of heat and aridity.
If possible, it is best to delay such pruning and shearing until after unusually hot weather. No one wants to be out working in the garden on a hot day anyway. More typical seasonable weather may not seem to be much cooler, but a few degrees can be a big difference to plants. Once exposed, inner foliage should adapt, and hopefully be resilient to heat before the weather gets hot again.
While young and thin, formerly shaded bark that suddenly becomes exposed can be damaged by sun scald. (Deciduous trees do not get scalded while defoliated in winter because the intensity of sunlight is diminished at that time of year.) Sun scald of bark is much more serious than foliar scorch because it kills bark, leaving open wounds on main limbs and trunks. Decay within these wounds compromises structural integrity, and can ruin otherwise healthy trees.
Although rare, spontaneous limb failure can occur in some trees during warm weather, particularly if humidity increases and breezes remain minimal. It sounds silly, but warmth accelerates vascular activity, possibly until foliage becomes too heavy for the limbs that support it. If limbs break, they can cause major disfigurement, and detrimentally expose bark of inner limbs and trunks.
Highlight: ‘Mystic Spires Blue’ salvia
Once it gets started in late spring, ‘Mystic Spires Blue’ salvia has potential to bloom until autumn. It only needs older floral spikes pruned away as they fade (deadheading) to stimulate new bloom. If it gets overworked and lanky without deadheading, it can be cut back in the middle of summer to start a new bloom cycle all over. It can get more than three feet tall and almost three feet broad.
Butterflies and hummingbirds really dig the rich purplish blue floral spikes, which might be a foot tall. The deep green foliage is technically evergreen, but it does not matter. All growth should be cut back to just a few inches above the ground in winter. ‘Mystic Spires Blue’ salvia likes richer soil and a bit more water than what drought tolerant salvias want. Warm and sunny exposure is best.