Page 27 - Silver Lakes July Issue 2024

GARDENING

BUMPS ON PLANTS

By Elize Malan

rees often have interesting swellings ground symptoms will be the wilting,
on their trunks or branches. Shrubs, yellowing and premature death of plants.
Tleaves and even roots can develop
lumps and bumps, too. Crop rotation in vegetable gardens will
prevent the problem.
Tree burls
Burls on tree trunks are benign growths Always buy healthy plants from a reputable
that do not harm the tree. The cause is nursery. Plant French marigolds, Zinnia and
often difficult to determine. When a burl Salvia to suppress root-knot nematodes in
forms in response to an injury to the tree, the garden.
the hard woody nature of the burl will wrap
around the wound and protect the tree The good galls
from further damage. These are the nitrogen-fixing nodules that
develop on the roots of legumes. Plants
Removing burls can create large wounds such as beans and sweetpeas, and trees
that the tree will have to recover from, and such as Erythrina abyssinica have this
it is not advised. ability.
The large woody swellings are In vegetable gardens, a cover crop of
hemispherical in shape. They often bear legumes will boost the nitrogen level of
many buds and, sometimes, sprouts. The the soil. Known as a “green manure”, it is
burls of black walnut, coast redwood, sugar tilled into the soil to provide slow-releasing
maple and black cherry are highly prized by Tree burls nutrients for future plants.
woodworkers for their beautiful swirling or
“bird’s eye” grain. Planting healthy plants and giving the
wounds caused by planting, cultivation, optimum care afterwards will prevent
Plant galls insects or nematodes. gall formations. However, remember that
Galls and tumours can differ in size and nature rules and not all lumps and bumps
shape and occur on both woody and A gall is formed at the crown of the plant can be prevented or cured.
herbaceous plants. They can be caused or where the stems and the roots meet (as
by genetic mutation, injury, insects, fungi, in roses). Crown gall will prevent water and
bacteria or a combination of more than one nutrient flow and the plant will eventually
problem. die. It is highly contagious and will spread
through the soil.
The swelling occurs as cells divide more
rapidly than normal (hyperplasia) and/ Fruit trees, grapevines, almond and walnut
or due to excessive cell enlargement trees are prone to this bacterial infection.
(hypertrophy). Marguerite daisies and some Kalanchoe
species show early signs of deterioration
By boosting the nutritional value of the soil, when infected.
some of the causes can be eliminated. Erythrina abyssinica
Remove the infected plant and change the
The galls on lemon tree leaves are caused soil before replanting. References:
by psyllids or jumping lice, and only affect https://uconnladybug.wordpress.com/2011/04/20/
the appearance of the leaves. Root galls galls-burls-explained-sort-of/
These are caused by root-knot nematodes https://www.freshquarterly.co.za/crown-gall/
The most common bacterial gall disease that have a wide host range and widespread https://treenewal.com/what-are-tree-burls/
is crown gall. This soil-borne bacterium distribution. Below-the-ground symptoms https://piedmontmastergardeners.org/article/the-
magic-of-legumes/
enters the roots of the host plant through will be swollen knotted roots; above-the-
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Plant galls Root galls

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