Galls are "tumor-like" growths that plants create in response to damage by certain other organisms including insects and bacteria.

Crown gall is so named because the galls form near ground level just above the crown. This disease is caused by a bacteria nemae Agrobacterium tumefaciens.

Infected canes or branches will lose vigor and eventually die.

The bacteria that causes lives in the soil and will probably infect the next plant placed there as long as it is susceptible. So, you guessed it, you can prevent this disease by replacing (or originally planting) disease resistant plants.

If you have a plant that has crown galls, never cut on it with a saw or pruning shears without sterilizing them before using on another plant. That is a key way of moving the bacteria around.

There are few, if any, antibiotics that can be used successfully on plants. Also, by the time the gardener discovers the galls, it is probably too late to do anything about it.

Unfortunately, about the only treatment is to dig out the entire plant and be sure to plant a non-susceptible species.

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.

Some trees and shrubs resistant to crown gall:
Abelia
Ailonthus - Tree-of-heaven
Amelanchier - Serviceberry
Berberis - Barberry
Betula - Birch
Buxus - Boxwood
Calluna - Heather
Carpinus - Hornbeam
Catalpa
Cedrus - Cedar
Cercis - Redbud
Cladrastis - Yellowwood
Cotinus - Smoketree
Cryptomeria
Deutzia
Fagus - Beech
Ginkgo - Maidenhair tree
Gymnocladus - Kentucky Coffeetree
Ilex - Holly
Kalmia - Mountain Laurel
Koelreutena - Goldenrain tree
Laburnum - Goldenchain tree
Larix - Larch
Leucothoe
Liquidambar - Sweet Gum
Liriodendron - Tuliptree
Magnolia
Mahonia - Oregon grape holly
Nyssa - Sour Gum
Picea - Spruce
Pieris - Andromeda
Pyracantha - Firethorn
Rhus - Sumac
Sambucus - Elderberry
Sassafras
Tsugo - Hemlock
Zelkova

 

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