by Ken Lain, the mountain gardener
On the Go Answer – Readers Digest Condensed Version of this Article
October is the ideal planting season for the central highlands of Arizona.
Garden Alert! Powdery Mildew spreads dangerously through gardens!
Powdery Mildew looks like powdered white splotches covering the leaves.
Spray the entire plant from top to bottom with ‘Copper Fungicide.’
A unique opportunity awaits fruit trees in spring. Berries, Grapes, figs, and the rest of the summer fruits rejoiced with monsoon rains with a record harvest. An April frost did not allow this blockbuster harvest from local fruit trees. Let me explain.
Fruit trees like apple, pear, peaches, plum, apricot, and cherries produce heavy fruit every other year. Trees set fruit heavy one year and rest the next. That is not to say they don’t have fruit yearly; the harvest is heaviest every other cycle. 2022 is a no-fruit season, and your trees spent the year sending deep roots with increased top growth. Next spring will produce a HUGE fruit crop, but you need to prepare your trees.
Here are two easy garden tasks you should take to maximize next year’s fruit harvest, both in size and quantity of fruit. Before Halloween, feed all your spring blooming and fruit trees with Watters 6-4-4-7 ‘Fruit and Vegetable Food.’ This organic food has 7% Calcium for increased fruit size and deeper flavors. Apply now and again in March for a blockbuster harvest next spring.
Local fruit trees are deciduous; they lose their leaves in Autumn. When the last fall leaves have dropped from your trees, spray the bare branches with Horticultural Oil. This fruit-friendly pest killer cleans your tree of insects and diseases for bug-free growth next spring. Repeat this spray in April. This one-two punch will increase next year’s blossoms and fruit for a heavy harvest.
Thursday’s Autumnal Equinox, the Sun is exactly above the Equator, and day and night are of equal length. It is the start of the fall planting season, especially for larger shrubs and trees like aspen, maple, spruce, and pine, but I would extend the season to other plants for the central highlands of Arizona.
October is the ideal planting season for Autumn mums, snapdragons, pansies, and so many other fall and winter blooming flowers. Autumn vegetables are best planted before Halloween as well. Autumn hardy broccoli, spinach, lettuce, kale, and all hard herbs are planted by the end of October.
Garden Alert! Powdery Mildew spreads dangerously through vegetable and flower beds, killing plants. This disease is circulating quickly, taking over entire gardens. Waves of diseased samples are flooding the garden staff, enough to sound the alert to gardeners.
Powdery Mildew is one of our most prevalent and recognized plant diseases in the rainy season. Virtually no plant is immune, but some are more susceptible than others. Lilacs, crabapples, phlox, monardas, roses, grapes, squashes, and cucumbers are likely targets for this powdery pest.
Recognizing Powdery Mildew – Take a close look at the photo of a squash leaf in my garden. Powdery Mildew looks like powdered white splotches covering the foliage and stems. There are several types of powdery mildew fungi, but they all look the same.
Photosynthesis is impaired if enough of the leaf surface becomes covered. It stresses plants, and severe infections weaken a plant’s health. Infected leaves often drop prematurely. It is a particular problem for edible crops since insufficient photosynthesis diminishes the flavor of the fruit or vegetable. If buds become infected, they do not open or mature at all.
Mildew is Host Specific – Powdery Mildew fungi are Host-specific, meaning the different powdery mildew fungi will not infect other plants. The Powdery Mildew on your lilacs will not spread to your grapes or roses.
Cause and Effect – Powdery Mildew seem to be everywhere. All Powdery Mildew thrives in the same conditions. They overwinter in plant debris and produce spores in spring carried by the wind, birds, insects, and splashing water. The growth and spread of powdery Mildew are encouraged by dampness, high humidity, poor air circulation, and crowded plants in the garden. All these conditions appear in the mountains of Arizona through our monsoon season.
Controls – First and foremost, choose healthy plants from your garden center. Healthy plants are less likely to become diseased and can better fend for themselves once an attack happens.
Infected Plants – Just a little work fends off pesky Powdery Mildew. Remove and destroy all infected plant parts, especially yellow leaves and those covered by white spores. Spray the entire plant from top to bottom with ‘Copper Fungicide.’ Try to water infected plants at ground level to keep leaves as dry as possible.
Spray weekly until new leaves emerge clean and disease free. At this stage, feed your plants, and they will take off with new growth. If you aren’t sure, consult one of the plant experts here at Watters Garden Center.
Please – Powdery Mildew spreads quickly to other plants. If you bring a leaf sample with you, place samples in a ziplock bag or jar to contain the spores and prevent spreading here at the garden center. Thank you.
Pinterest board set up with local examples of Powdery Mildew. I trust it helps:) Follow our board for local updates.
Until next week, I’ll be helping local gardeners grow better gardens here at Watters Garden Center.