Mahonia plants are easy to grow and are very tolerant of a wide range of conditions, they are about as hardy as shrubs come. It’s quite unusual that your mahonia is not flowering. However, you should check its natural life cycle and whether you’re providing the best growing conditions for it. From experience, I have noticed they sometimes won’t flower if the soil is poor draining and waterlogged. They like moist soil but not sopping wet. They also need a least a couple of hours if sunshine, if it’s very shady, this might also prevent flowering.

Learn more by reading on below.

Irregular life cycle

Mahonias produce brilliant yellow flowers in winter and spring, that is, between December and March. This is often followed by a host of purple-red berries in the summer and autumn. However, with over 70 varieties of this plant, some do have blooming periods that are slightly off schedule. This may be why your mahonia is not flowering as expected, especially if it’s the first season since it was planted.

What to do

If it’s within the regular blooming time and your mahonia has no flowers, check what variety it is and when you should expect the flowers to appear. You may be surprised to learn that the flowers aren’t expected until summer.

Best growing conditions for mahonias to ensure they flower

Mahonia plants are extremely tolerant of the growing conditions they find themselves in. However, they do have some preferences. And some particular conditions and circumstances cause them harm, and so the mahonias do not flower.

Check here that you’re providing the best environment for your mahonia, which generally means moist free draining soil, although they are drought tolerant and full sun or partial shade.

Light and temperature

Mahonia likes to grow in partial shade or full sun, as mentioned above. While they tolerate direct sun, too much harm the plant and produces leaf scorch (sunburn) which I talk about here. This weakens the plant making it unable to produce foliage and flowers.

These plants tolerate a wide range of temperatures, even down to below freezing. But too much sun, and hence too much direct heat for too long, can cause the plant to lose too much water through transpiration through the leaves.

What to do

Create barriers for the plant to shelter it from the sun and the wind or position the plant in new spot once it’s dormant for winter.

Water

Too much water and not enough water, primarily affect the leaves on the plant. They turn yellow, curl up and die. (See Why are my mahonia leaves turning yellow?) The plant produces less energy because of this, which may affect how many flowers are produced and whether they fully develop.

What to do

Water the plant only in times of extreme dryness.

Soil

Mahonia grow in all kinds of soil – clay, loam, compost, sand and chalk. But they don’t like wet soil, and they really don’t like soil that’s waterlogged. Waterlogged soil, in particular, leads to fungal diseases which affect the whole plant, including the development of flowers. This may be why your mahonia is not flowering.

What to do

Create dry soil that can drain easily.

Fertiliser

Mahonias don’t require many nutrients as the plant grows and develops foliage, buds, flowers and berries. However, if you don’t fertilise once a year and your soil is lacking in nutrients, even the few nutrients that the mahonia needs may not be available to it.

What to do

You only need to fertilise mahonia at the start of the spring season.

Grow in the ground

These plants (even the small ones) need lots of room to spread out. Being squished in the pot is affecting its ability to bloom.

What to do

If you’re growing your mahonia (probably the smaller mahonia varieties) in a pot, transplant it into the ground as soon as the weather supports this.

Prune lightly to encourage more flower being careful not to remove flowering growth

You may have over-pruned your mahonia and cut off all the buds that would turn into flowers.

What to do

You only need prune your mahonia plant lightly to:

• Remove dead and diseased stems, branches, and leaves.
• Create the shape you want the plant to be.
• Remove old branches from the centre of the plant to create more air circulation.

When you prune your mahonia:

• Prune only one-third of the total number of branches each year.
• Remove only one-third of the length of the branch you do prune each year.
• Prune immediately after the flowers have finished blooming (in the spring).

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