September has arrived and daytime temperatures over the past few days have been in the upper nineties. The mere anticipation of cooler days as the fall season nears is all that it takes for the ardent gardener to want to till the soil, remove what the summer heat has burned, and plan for a newness of season and spirit.
The change is subtle to be sure, as temperatures may still rise into the upper nineties on a daily basis after the arrival of the first real cool front. The extreme heat of summer will pass over the next few weeks and the fall growing season will commence. Seasonal change is also apparent in the length of the day as we are rapidly approaching the fall equinox when days and nights are equal in duration.
September’s gardening calendar includes the following activities:
Hurricane Preparedness: Hurricane Laura did NOT come our way! While that was certainly a great relief to us, the hard reality is that hurricanes in the Gulf are going to make landfall somewhere. Hurricane Laura served as a poignant reminder for everyone to always make preparations in a timely manner. Remember, mid-September marks the height of hurricane season.
Pruning Shrubs and Bushes: September is also a good time to lightly trim unruly shrubs and bushes. Pruning too late in the season may encourage tender new growth which could be susceptible to cold weather. Be careful not to prune plants like bougainvillea, gardenias, camellias and azaleas at this time as these plants have already formed next spring’s floral buds. Pruning these plants now will result in fewer flowers next year.
Palms: In contrast to most landscape trees, September is the last month for transplanting palms and sagos for the year to ensure good establishment before cooler temperatures arrive.
Pesticide Applications: Some areas of the county have recently recorded daytime temperatures reaching the 100 degree mark. Avoid spraying insecticides, fungicides and other pesticides during the heat of the day when temperatures are above 90 degrees.200
The “carrier” of many liquid pesticides is petroleum-based and can cause some burning of leaves if applied when temperatures are high and plants are water-stressed or heat-stressed. Spraying should be done in early morning or late evening.
Divide Perennials: Late September is the time to divide spring-flowering perennials such as irises, Shasta daisies, gaillardias, cannas, day lilies, violets, liriope, and ajuga. Reset divisions into well-prepared soil with generous amounts of organic material worked into the top 6-to-8 inches of the soil bed.
Fall Vegetables: Vegetables to plant at the beginning of September include corn, cucumber, green beans, lima beans, pepper, squash and tomato. Toward the end of the month this list can be expanded to include broccoli, cabbage, carrots, cauliflower, celery, collard, endive, lettuce, mustard, onion, radish, and turnips.
Butterflies: September is a prime month to spot butterflies in landscapes. Some commonly observed butterflies include the buckeye, cloudless sulphur, giant swallowtail, great southern white, white peacock and zebra among others. It is quite easy to attract these delightful creatures to your garden by planting a variety of annual and perennial flowers.
Fertilization of Shrubs: Avoid the use of high nitrogen fertilizers on shrubs from late September on through early spring. Too much nitrogen applied this late can induce late succulent growth and possible winter injury.
Splitting Citrus: Soon after some areas received showers, I started receiving inquiries about the cause of citrus fruit splitting. This type of damage typically occurs when citrus trees rapidly take up water after heavy rainfall. The fruit expands and bursts the peel in a crack across the bottom or blossom end of the fruit.
The buildup of excess fluids produces sufficient internal pressure to cause the skin to burst. Young trees have the highest incidence of splitting. Fruit splitting occurs commonly on oranges, mandarins and tangelos. In contrast, grapefruits are rarely affected by this problem. Maintaining adequate and even soil moisture levels by regular irrigation during extended periods of dry weather is the best defense against fruit splitting.
Succulents: All potted plants are not created equal—at least not in their water requirements. So, don’t form a habit of watering cacti and similar succulents every time you water other plants on the patio or porch. Excessive soil moisture can result in damaged roots on cacti, jade plants, ponytails palms, etc.
Caladiums: Caladiums require plenty of water at this time of year if they are to remain lush and attractive until fall. Fertilize with ammonium sulfate at the rate of 1/2 to 2 pounds per 100 square feet of bed area, and water thoroughly.
September is a prime month to spot butterflies. Butterflies are attracted to landscapes containing a diverse variety of flowering plants.PHOTO CREDIT: Billy Jenke
