In Portland: Plant plum trees Mar 1 – Apr 26. In Bend: Apr 28 – Jun 23. Find your city below.
Difficulty
Easy
Sun
Full sun
Spacing
12 to 15 feet apart for dwarf or semi-dwarf trees
Planting depth
Graft union 2 to 3 inches above the soil
Frost
Hardy perennial; comes back every year
First harvest
First plums in three to five years
Italian prune plums have been a Northwest backyard staple for a century. European plums like Italian and Stanley fruit on their own; Japanese plums need a partner.
Pick a sunny spot with soil that drains well, and mix in an inch or two of compost.
Plant plum trees on your city's dates, 12 to 15 feet apart for dwarf or semi-dwarf trees. Graft union 2 to 3 inches above the soil.
Water deeply through the first two summers. Prune lightly in summer, not winter, which lowers the risk of silver leaf and canker. Thin heavy crops so branches don't snap.
Harvest: Pick when the fruit is fully colored, slightly soft and comes off easily. Prune plums for drying should hang until they wrinkle slightly at the stem.
Key numbers
3–5Years to fruit
Self-fertileEuropean plums
Summer, in dry weatherWhen to prune
Brown rotBiggest risk
Growing notes
What makes the difference in Northwest gardens, in plain language.
European or Japanese plums
European plums, including Italian prune and Stanley, bloom later and fruit on their own, which makes them the easiest choice for most Northwest gardens. Their dense, sweet flesh is great fresh, dried or baked. Japanese plums such as Shiro and Methley bloom earlier, have juicier fruit and ripen in mid-summer. Shiro sets a much better crop with another Japanese plum nearby, and Methley is a popular partner because it's partly self-fertile. In frost-prone spots, the earlier bloom of Japanese plums can get caught by a cold snap.
Why plums are pruned in summer
Plums and other stone fruits are prone to silver leaf and bacterial canker, which enter through pruning cuts in cool, wet weather. Cuts made in dry summer weather heal fast and stay clean. Prune lightly after harvest or in July, removing dead wood, crossing branches and tall upright shoots.
Heavy crops are common. Thin young fruit to 3 to 4 inches apart in early summer: the remaining plums grow bigger, brown rot spreads less between touching fruit, and branches are less likely to snap.
Harvest and brown rot
Brown rot is the main Northwest plum problem. It blights blossoms in rainy springs and turns ripening fruit into fuzzy gray balls that dry into mummies. Those mummies carry the fungus into next year, so pick them off the tree and the ground. Good airflow and thinning help a lot.
Italian prunes are sweetest when left to hang until they wrinkle slightly at the stem. Japanese plums soften quickly once ripe, so check every couple of days.
Common questions about growing plum trees
Do plum trees need a pollinator?
European plums like Italian prune and Stanley are self-fertile and fruit fine alone. Japanese plums such as Shiro do much better with another Japanese plum nearby.
What's the difference between a prune and a plum?
A prune plum is a European plum with dense, sweet flesh that dries well without fermenting at the pit. Italian prune is the classic Northwest variety, and it's just as good eaten fresh.
Why are my plums rotting on the tree?
That's usually brown rot, a fungus spread by wet weather. Thin the fruit so plums don't touch, remove any shriveled mummies from the tree and the ground, and pick promptly when ripe.
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