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How to grow Mahonia japonica and care guide
Last Updated on March 11, 2020 by John
The Mahonia Japonica prefers shade as it naturally grows in woodland setting but will grow just as well in semi-shade. At full maturity, it reaches a height of around 200cm and a wider spread around 400cm so makes quite a large evergreen shrub with plenty of interest in terms of colour all year round.
These are typically grown because of the dark green foliage along the bottom of the plant comprised of 5 to 20 leaflets depending on how old your plant is. But come winter is when it really comes into its own with the leaves taking on a reddish-purple hue and then give way too large, long stocks of bright yellow flowers they are best known for and what a magical display they make when not much else is flowering.
Perfect for providing colour from late autumn to early spring
The scent is similar to that of lily of the valley. The bright yellow flowers come out of the ends of the leaves but if you have a smaller plant that you’re growing in pots they might shoot directly out of the centre and they usually start flowering from late autumn through to early spring. After flowering, they give way to equally attractive purple fruit.
Allowing ample space when planting
Mahonia Japonica is considered the smaller of the media varieties and yet even in its smaller size it still grows quite large as already mentioned as around 2 meters tall by nearly twice as wide.
The plant is very hardy and will grow in almost any soil including moist soil, dry soil, sand soil, or heavy clay. However, it is recommended that you grow it in well-draining soil no matter what the conditions might be.
How to plant a mahonia
If you have a new Mahonia Japonica it is recommended that you prepare the site by mixing in bone meal or fish, blood and bone into the soil to help encourage the root growth. Soak the roots in water for at least 20 minutes in a bucket of water before planting so that they do not dry out.
Very hardy but are best protected from cold drying winds as they damage foliage and flower buds
These do well in woodland areas and will survive in shade as long as they are protected from the cold winter wind. They work very well as a screen because of the tall and bushy nature. The leaves have sharp spikes on them as well, perfect for inhibiting intruders.
Mulch around the base of plants
As mentioned they are very strong shrubs but you can help them out here and there by adding mulch around the base to protect the roots especially if you live in a very cold area with harsh winter weather. If you recently pruned your Mahonia you should always add some mulch to help it recover and retain moisture.
Pests and diseases
Mahonias do not suffer from many issues but rust and powdery mildew can become a problem but its not a huge issue and easily treated and rarely leads to the plant dying.
Thankfully you can easily identify the signs of these fungus issues as soon as they arise and treat them with a fungicide as soon as you notice any issues.
It is best to avoid regular pruning on a Mahonia Japonica but you can prune to remove dead, damaged, or diseased growth at any point. You can also prune to maintain the size of the plant and the shape after what you should apply some slow-release fertiliser and mulch around the base of the plant.
If you are going to prune it’s recommended that you do it in spring-early after flowering but if you have a dead or diseased branch you can remove those immediately as soon as you notice them.