Here’s how to protect your peach trees from deadly leaf curl disease (2024)

In the Garden

Q: After losing a prized peach tree to curl disease, I recently ordered a ‘Frost’ peach because I heard it is highly resistant to the disease. Are there other peach trees that are also resistant?

A: Peach leaf curl is a fungus disease that causes distorted, swollen and curled leaves and twigs. Infected leaves often drop early, and repeat infections usually kill the tree in two or three years.

Timely sprays in the middle of winter are required to prevent the disease from infecting swelling buds.

For many years, ‘Frost’, a flavorful, yellow-fleshed variety, was the only curl-resistant peach available. In the past few years, however, new curl-resistant peaches have come on the market, making for a wider range of peach flavor available for the home gardener.

‘Avalon Pride’ ripens early. Its yellow flesh is delicious eaten fresh, canned or in pies.

‘Mary Jane’, also with yellow flesh and tasty eaten fresh, is known for setting fruit, even in cold springs.

If you prefer a white-fleshed peach, the fruit on ‘Salish Summer’ (previously known as Q-18) is sweet and flavorful, and has attractive flowers.

When it comes to flavor, however, ‘Indian Free’ is considered one of the best-tasting peaches of all-time. The heirloom variety was grown at Monticello by Thomas Jefferson and produces heavy crops of large, aromatic freestone peaches with white flesh marbled with crimson stripes. Unlike all of the peaches listed above, ‘Indian Free’ must have a different variety of peach growing nearby for cross pollination in order to produce fruit.

Be aware that even if a peach is resistant to peach leaf curl, it’s still susceptible to the disease for the first few years after planting. To get your tree off to a healthy start, you’ll need to spray lime sulfur once in late December and twice more at two-week intervals for the first five years. After that, no further sprays to control peach leaf curl should be required.

Q: Do genetic dwarf peach and nectarine trees produce well in the Puget Sound region?

A: Genetic dwarf peach and nectarine trees are the result of years of breeding. They are naturally compact trees that rarely exceed 6 feet tall. Grown in pots or planted in the garden, one tree is capable of producing an impressive amount of fruit in a single year.

Unfortunately, genetic dwarfs are highly susceptible to peach leaf curl. They won’t survive unless they are sprayed in a timely manner, or otherwise protected from the disease. Another problem is that in our mild Puget Sound climate, unless we have an unusually hot summer, there often isn’t enough heat for the fruit to ripen and develop good flavor.

Fortunately, we can take advantage of an old English method called ‘eaves dropping’ to solve both problems.

English gardeners discovered they could prevent peach leaf curl infection by covering the trees with plastic in order to keep the buds dry when infection normally occurs in winter. With this knowledge, they plant and espalier their peach and nectarine trees under the eaves of the sunny south side of their houses. They fasten plastic sheeting to the eaves that covers the trees and keeps them dry in winter.

The trees not only remain curl free, the added warmth and reflected sunlight on a south wall fosters earlier ripening and more flavorful fruit.

Genetic dwarfs are the perfect tree for eaves dropping. They stay small, and they’re easy to espalier. Just don’t forget to open the plastic sheeting during the bloom period to allow free access to pollinating insects. Likewise, open the plastic on hot sunny days to prevent burning the foliage.