The holm oak makes an impressive impression. However, as most of it is not adapted to our climate, it needs a little more care, especially in winter.
The holm oak (Quercus ilex) impresses with its bizarre and gnarled growth habit. However, the plants are rarely found in the wild in Germany. Because the holm oak loves warmth and feels much more comfortable in the Mediterranean area than here. In our latitudes, it only survives the winter in climatically particularly favorable regions - for example in the Rhine Valley or around Lake Constance. The plants are therefore preferably cultivated in tubs and offer a pretty eye-catcher on the balcony or terrace.
While the holm oak can grow up to 20 meters in the open air, the plants in the bucket are at least about two meters tall and thus offer an impressive sight. If care errors are avoided, the holm oak will prove to be robust and easy to care for. What is important when caring for beech plants can be read in the following.
Water the holm oak properly
Horn oaks don't like drought. If the plants are outdoors, they should be watered regularly in summer as soon as the top layer of soil appears to have dried out.
Tip: Always water directly at the roots and avoid pouring the irrigation water over the leaves or the entire tree.
Particular care must be taken with young plants. Their root system is not yet stable enough to obtain sufficient liquid from the soil. Depending on the weather, daily watering may therefore be necessary.
In winter there is less watering. But the soil must not dry out here either. Therefore, check the plant regularly and, if necessary, water the holm oak on frost-free days.
Tip: The plants are better protected from drying out if a layer of mulch is applied to the soil.
What should be considered when watering the holm oak in the bucket?
The holm oak has only limited substrate available in the tub and must therefore be watered regularly. The earthshould always feel slightly damp. However, it is important to avoid waterlogging.
Tip: Since waterlogging is particularly common in potted plants, you should always make sure that there are enough drainage holes in the planter. Furthermore, a drainage made of gravel or expanded clay in the bottom of the vessel protects against waterlogging.
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- Soil must not dry out
- Water outdoor plants occasionally
- Water potted plants regularly
- Avoid waterlogging
- Put water directly on the roots
Fertilize the holm oak properly
Hospital oaks are quite undemanding when it comes to fertiliser. For outdoor plants, it is sufficient if you mix the substrate with mature compost or another organic long-term fertilizer when planting. If planted in spring, fertilization should be repeated in summer.
In the bucket, fewer nutrients are available to the plant. Fertilization plays a bigger role here. A complete fertilizer can be applied fortnightly during the growth period.
Tip: Since the soil in the pot is used up quickly, it is best to repot annually and replace the soil completely.
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- Outdoor plants receive compost twice a year
- alternatively another complete organic fertilizer can be administered
- Fertilize potted plants during the growing season
- Commercial complete fertilizer can be given every 14 days
Pruning the holm oak correctly
Regular pruning measures are not absolutely necessary for the holm oak. The plants develop their characteristic bony shape most beautifully when the hobby gardener intervenes as little as possible.
However, the plants tolerate pruning and can be pruned back in early late winter if the need or need arises.
Tip: Choose a frost-free and cloudy day for pruning, without precipitation and without blazing sunshine.
Sick or dead branches should be generously removed. However, you should not cut back into the old wood. All shoots that you find too long and affect the growth habit of the tree are shortened over an outward-facing eye. Also trim branches that are crossing or growing inwards.
Warning: Use when pruningalways sharp and clean garden tools. If the cutting tools are not disinfected, bacteria and fungi can penetrate the plant. Fuzzy scissors do not leave clean cuts on the twigs and branches, but bruises. These would damage the plant unnecessarily and provide an entry point for pests and pathogens.
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- Pruning not absolutely necessary
- remove diseased and dead branches
- Growth habit preserved by pruning
- Use clean and sterile cutting tool
An overview of the most important care measures
| Care Measures | Explanation |
|---|---|
| Casting | • The soil must not dry out. • Outdoor plants should be watered during prolonged periods of drought. • Potted plants are watered regularly. • Waterlogging should be avoided.• The water should be poured directly onto the roots. |
| Fertilize | • Outdoor plants receive organic fertilizer in spring and summer. • Potted plants receive a complete fertilizer regularly during the growing season. |
| Cut | • Pruning is not absolutely necessary. • The plant develops its characteristic growth form without the hobby gardener having to intervene. • Remove old and dead branches. • The Holm oak tolerates pruning well. |
Wintering the holm oak properly
The winter hardiness of the holm oak in Germany is unfortunately to be regarded as limited. The Mediterranean plants only survive the winter outdoors in particularly mild regions, such as wine-growing areas. The trees can also withstand frosts down to -15 degrees for a few days, but would certainly freeze to death in harsh locations if there were persistent permanent frosts.
If the holm oak is outdoors, it must also be protected from strong sunlight. Intense winter sun can cause the bark to crack. This weakens the trees and can make them more susceptible to disease. A rather shady winter location is therefore advisable. If this cannot be guaranteed, the trunks should be protected with garden fleece:
How do you overwinter the holm oak in a bucket?
Potted plants are brought into the house before the first frosts. A certain frost tolerance can only be awarded to outdoor plants. If the holm oak is in the bucket, there is a risk that the planter and the roots will freeze throughcan no longer absorb nutrients, which leads to the death of the plant.
The holm oak in the bucket must be frost-free over the winter. The temperature differences should not be too great. Constant temperatures between eight and ten degrees are ideal. The winter quarters should be bright. An unheated conservatory or bright stairwells are very suitable.
Tip: Since these are evergreen plants, the winter quarters should be as bright as possible. Otherwise the leaves will fall. Most of the time, however, the plants will reliably sprout again in spring.
Recognize diseases and pests on the holm oak
Detecting and controlling powdery mildew
The holm oak is a robust plant that rarely gets sick. Occasionally there is an infestation of powdery mildew. The hobby gardener can easily recognize this by a whitish coating on the leaves. The topping is reminiscent of flour. In the case of advanced mildew infestation, chemical pesticides will inevitably have to be used.
Tip: If the infestation is lighter, rubbing the leaves with milk can help.
Detecting and controlling scale insects
Particularly in the winter quarters there is a risk of infestation with scale insects. The pests can be seen with the naked eye and can often be driven away simply by treating them with a hard jet of water. Home remedies such as nettle manure or garlic are also effective.
Tip: In the case of an infestation with aphids or whiteflies, however, no intervention by the hobby gardener is usually necessary.
Avoid care mistakes
To keep the plants he althy, there are a few things to keep in mind when caring for them. The plants are particularly sensitive to drought. Even in the winter quarters, the plants must not dry out. In addition, the potted plants should only be moved to the balcony or terrace when frost is no longer to be expected.
Help - my holm oak is not blooming
You have planted a holm oak and are now waiting in vain for it to bloom? There is probably no maintenance error, but you will still have to be patient. The plants of the same sex do not produce their first flowers until they are 30 to 40 years old.