Mahonia: Growing, Caring, and Pests

Growing Mahonia: Caring and Planting Guide (UK)

Mahonia shrubs are evergreen and can tolerate temperatures as low as -15degC. Mahonia media Charity’, which is the most common variety, can reach a height of 2m/6ft. However, there are smaller varieties that can be used as ground cover. Sometimes known as Oregon Grape. The yellow flowers are usually produced between November and February, with blackberries often following.

What’s The Best Shade For Growing Mahonia?

Mahonia likes to be in partial shade. However, they can thrive in full sun. They can grow in any soil condition, including clay, chalk, and even sand. They only require watering in extremely dry conditions when grown in open soil. Mahonia can withstand neglect well, as their nutrient needs are low. They also grow well with minimal pruning. A simple annual pruning is enough to keep them in control. 

Can you Grow Mahonia in Pots or Containers?

Many produce beautiful flowers and all of them are evergreen. If they are not neglected, they rarely become infected or suffer from other diseases. They are not suitable to be grown in containers.

Mahonia

Taking Care of Mahonia

Mahonias can be very easy to maintain, but they do require a little attention. A September mulch made from well-rotted garden compost will help keep the weeds under control and prevent the ground from freezing in winter.

Mahonia shouldn’t be fed nitrogen-rich fertilizers as they aren’t able to handle it. They will still appreciate an April feed with some blood, bone and fish scattered about and lightly worked into the soil. Mahonias that are established should not be watered for long periods of time. Water the Mahonias if they are in need, but not too often.

Pruning Mahonia

Mahonia will benefit from an annual prune. This will help keep your Mahonia’s plant at a manageable size and to prevent it from crowding the center.

Mahonia can be pruned any time of year, without causing damage to the plant. However, it is best to prune Mahonias soon after they have finished flowering. This is usually March-April. This will increase their chances of producing flowers later in the year.

Allow them to reach their full height before you prune. They both look and grow taller as tall plants. They will not grow into a mound if you try to trim them.

Trim the stems that are older than a quarter of an inch from the center of the plant. To keep the plant manageable in size, trim any outer stems.

Pests and Diseases

Mahonia Rust

Rust can affect all varieties of Mahonia, but bealei and Mahonia aquifolium are the most affected. Cumminsiella mirabilissima is the Latin name for this fungus. You will notice small, deep red marks at the top of your leaves. The leaves will turn brown or rusty-coloured powdery marks if you turn them over.

Rust can grow in moist conditions with little ventilation. Mahonia rust can be treated by regularly burning and picking up all the leaves that are on the ground. To improve air circulation, you can prune the centre of the plant as mentioned above. Spraying fungicides to fight rust may be an option.

Powdery Mildew

There are brown spots on the leaves’ tops and light grey fungal growths on the leaves’ undersides. Lower-level leaves are more susceptible than those higher up in the plant. This is due to fungus. The causes are damp conditions, poor air circulation, and cold soil. You can avoid these conditions. It may be necessary to relocate your plant to a more sunny spot. If you don’t take care of the Mahonia, it will eventually die.

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