Question: What is wrong with my plum tree? Many of the plums are misshapen, much larger than the others and inedible. Could this be the result of our cool, wet spring?
Answer: I think your tree is suffering from plum pocket (also known as bladder plum), a disease caused by the fungus, Taphrina pruni.
Plum pocket affects the leaves, twigs and fruit of stone fruits (e.g., plums, peaches, apricots and cherries). Young leaves can be thickened and curled. Twigs and small branches can be distorted and swollen. Affected branches sometimes produce clusters of short weak shoots (called Witches’ brooms).
The most obvious abnormality associated with plum pocket is the swollen, bladder-like fruits that lack stones (seeds). Affected fruits enlarge early in the season, turn brown, then black and shrivel.
The shriveled fruit eventually becomes covered with velvety gray fungal spores.
Did our prolonged cool weather cause this problem? Cool and wet weather conditions promote the germination of many fungal spores. Recent weather patterns might have contributed to the appearance of the problem.
What can you do about plum pocket? The fungus overwinters in infected shoots and fruits. Therefore, prune out and destroy infected twigs, branches and fruit which will be a source of infection next year. Rake up and destroy fallen fruit. Do not compost affected plant parts.
If plum pocket has affected most of the fruit on your tree, consider more aggressive control measures in the future. Apply a fungicide labelled for plum pocket the following year before the buds open and shoots start to grow. See pnwhandbooks.org/plantdisease/host-disease/prune-plum-prunus-spp-plum-pockets for details.
We think this disease is uncommon in our area, but your report is the third we’ve received this season. To get a better sense of the prevalence of plum pocket in Clallam County, we are asking local gardeners to report the occurrence of plum pocket to the Master Gardener Plant Clinic.
Call 360-417-2514 and leave a voicemail or submit a report (and photo) by email to firstname.lastname@example.org.
Question: When does it make sense to use a soaker hose versus drip irrigation?
Answer: Both soaker hoses and drip irrigation allow you to apply water slowly at the base of your plants, keeping foliage drier, limiting fungal diseases, and minimizing the loss of water through evaporation and run-off.
Soaker hoses have thousands of tiny pores that drip water slowly and evenly along their entire length. They are usually made of a combination of recycled rubber and recycled polyethylene and are relatively inexpensive.
Soaker hoses are easy to use. They connect to typical outdoor faucets and can be moved around just like garden hoses.
When you water with a soaker hose, you water not only the plants you want to water but everything between them (e.g., weeds or open ground). Because water is delivered at the same rate along the length of the hose, some plants situated next to a soaker hose might be over-watered and some might be under-watered if their water requirements differ.
Drip irrigation is a system of small polyethylene tubes and emitters that delivers water right where you want it. Drip systems have many parts (e.g., backflow preventers, pressure reducers, filters) and can be purchased as kits or individual components.
Drip systems must be carefully planned. They take more knowledge and effort to install. But drip systems can be customized to meet the needs of your garden or landscape. Emitters can be spaced evenly for row crops or intermittently for plants spaced further apart, such as trees, shrubs and perennials. You can use different sized emitters (or numbers of emitters) at different points along the line so that different plants (or sections of the garden) receive more water than others.
How can you best use these two types of irrigation? Soaker hoses work well for plants with similar water requirements that are planted in a row. They work best on level ground and in raised beds.
Drip systems make sense for larger gardens with different zones of plants with different water requirements. They work in sloped areas due to the pressure regulators that are part of the system and can be used for watering in-ground plants as well as plants in containers and smaller planters.
Question: What are pineberries? Can I grow them from seeds?
Answer: Pineberry (Fragaria × ananassa var. Pineberry) is a white to pinkish strawberry cultivar with red seeds and a pineapple-like flavor. They are closely related to red garden strawberries and are the result of crossbreeding (hybrids), not genetic engineering.
Pineberries lack pigmentation because they don’t produce anthocyanin, the compound that gives strawberries their red color. Pineberries should not be confused with white alpine strawberries, Fragaria vesca var. Albocarpa, which have white berries and white seeds.
Pineberries have growth habits and requirements like red garden strawberries. Plant them in full sun in a slightly acidic, well-drained soil that is rich in organic matter. They can also be grown in containers.
Unlike red garden strawberries, pineberries are not self-fertile, meaning they require cross-pollination by a second cultivar for good berry production. Red garden strawberries can cross-pollinate pineberries.
I would not recommend growing pineberries from seed. As hybrids, pineberry seeds will not produce the same type of plant as the original. You are much better off purchasing bare root or potted pineberry plants.
Jeanette Stehr-Green is a WSU-certified Clallam County Master Gardener.
Make sure to join us for the upcoming Green Thumb presentation, “Mushroom Cultivation, Carbon Sequestration and Regenerative Soil” presented by Lowell Dietz via Zoom from noon 1 p.m. Thursday, July 28. (Get a link at extension.wsu.edu/clallam/master-gardener-calendar, or call 253-215-8782 with meeting ID 920 0799 1742, passcode 709395). Green Thumb presentations cover basic gardening topics relevant to most home gardeners. Seminars are free, but donations to help support the WSU Clallam County Extension Master Gardener program or Master Gardener Foundation of Clallam County are appreciated.