With a wetter than normal spring, the list of tasks to do in the garden is longer than usual. Additionally, wet weather tends to cause a spike in potential plant diseases, so maintenance is critical in order to mitigate the risk. Below are just some of the key tasks for many gardens.
Task No. 1: Mulching
Mulch provides numerous benefits to your garden and soil. The key with mulching is to apply it thick, ideally 3 to 5 inches deep. No “pixie dust” sprinkling. A study by Dennis Pittenger done in 2005 showed the amount of water retained in soil from mulching differs based on material and thickness. Soil with yard waste (grass/leaf clippings) applied 3 inches deep had half as much water lost to evapotranspiration as an exposed soil. In comparison, bark applied 3 inches deep resulted in only 30 percent of water lost. This alone is reason to mulch.
In addition to water conservation, mulch insulates the soil, resulting in cooler roots and healthier plants. The cooler temperature encourages earthworms to live closer to the soil surface. Worms active near the surface means more castings (manure) and pliable soil closer to the plant root systems. Without mulch, they will dive deeper into the soil, where it is darker and cooler.
If you are tired of hand weeding, I recommend mulching as a method of suppression. Once again, effectiveness is related to thickness applied. In my dream world, I would lay down 6 inches of mulch and have no weeds poking through. Cut down large weeds and, ideally, apply mulch before weeds germinate. Sheet mulching (adding layers of cardboard) under the mulch aids in weed suppression. The infamous bindweed and Bermuda grass can find their way out from under the cardboard/mulch, so apply a bit wider than where these weeds are growing.
I have used a variety of mulches – compost, wood chips from tree companies, straw and horse manure. Compost is the gold standard. Not only does it provide all the benefits of a mulch, but it adds nutrients to the soil. Negatives are the cost and the need to reapply it each year, due to its rapid decomposition.
Wood chips from tree companies are my second favorite. These are reasonably priced, depending on the tree company. Ensure they are not from diseased trees, black walnuts, which suppress growth of plants, oleanders (if used around horses) or palms (palm fronds do not chip well). Over time, these wood chips breakdown and provide nutrients to the soil.
Straw is cheap and easy to use – the flakes break easily off the bale and spread relatively well. There is no real nutritional value from straw and it can blow around, sometimes creating a mess.
Horse manure can usually be acquired inexpensively, sometimes free, from horse barns. Make sure it comes from the oldest pile so it does not burn your plants. It is a manure, but as far as manures go it is mild (low in nitrogen). Be careful, as you may get oats popping up. If you do, they are easy to pull out as they are growing in the manure and not the soil.
Task No. 2: Prune once-blooming spring plants
Now is the time to prune once-blooming spring plants. If pruned in the fall you run the risk of cutting off the following season’s blooms. Some examples are camellias, forsythia, quince and wisteria.
Task No. 3: Paint young tree trunks
Young trees are susceptible to sunburn since they do not have a thick layer of bark. To prevent this, apply white interior latex paint diluted 50 percent with water. Make sure to focus on the west and south sides. Sunburn can blister the tree trunk allowing pathogens and pests to enter.
Task No. 4: Disease maintenance
Peach leaf curl and foliar fungi have been especially bad this year due to the wet weather. For peaches and nectarines affected by peach leaf curl, the only thing to do now is clean up fallen debris. Pick up fallen leaves to prevent the spread of spores. Fertilize with a mild nitrogen if the tree has defoliated. Remember, the proper control/prevention is liquid copper applied during the dormant season, not now.
I almost never treat for powdery mildew, leaf spot or rust. The warm, dry weather tends to eradicate it. However, if a plant is really suffering, then spray with neem oil or sulfur dust/spray. Be careful; once temps reach above 85, these treatments can cause burn. Bacillus subtilis, a bacterium (sold under the name Serenade) works to control leaf spot and powdery mildew and can be sprayed in hot temperatures. Be sure to pick up fallen leaves to prevent the spread of spores.
Fireblight is a bacterial disease that affects plants of the rose family, but most often shows up on pears (fruiting and ornamental) and apples. It looks like someone took a blowtorch to the limbs. For control, cut the affected limb off or at least a few inches past the last sign of infection. The key is to prevent the bacteria from entering further into the tree. Fireblight can be eradicated if caught in time. Trees can live for years with an infection, but over time it will weaken and eventually kill the tree. If you see any signs on your tree, act now. Be sure to disinfect pruners between cuts with a 10 percent bleach solution.