Thuja is a very undemanding plant from the conifer family. Therefore, frequent fertilization is not only unnecessary, but even harmful. What do you have to consider if you want to properly fertilize a thuja hedge? Which fertilizer is suitable and when should you fertilize?
How should you properly fertilize a thuja hedge?
When fertilizing a thuja hedge, you should not fertilize in the first year after planting, then in spring and late summer, but never in autumn or winter. Suitable fertilizers are conifer fertilizer, compost, horn shavings, blue grain or Epsom s alt. Particular caution should be taken when over-fertilizing, which can damage the plant.
When is fertilizing Thuja necessary?
Thuja prefers loose soil that should not be too nutrient-rich. That's why you should never overdo fertilizing. If you use fertilizers from the garden supply store, be sure to follow the instructions and reduce the dosage slightly. Under no circumstances should you give more than what is listed on the package.
Fertilizing is only really necessary for very young plants. Even if the hedge looks a bit stunted or has yellow and transparent needles, fertilizing can be helpful.
Fertilizing for the first time
If you have bought and planted Thuja in bales, do not fertilize at all in the first year. These plants are already sufficiently supplied with nutrients.
For bare-root thujas, wait two to three weeks before fertilizing for the first time. Then new fine roots have already formed that are able to absorb the fertilizer.
The right season to fertilize thuja
It is best if you fertilize the tree of life in spring. Long-term fertilizer is recommended for this. Later in the year you can apply further fertilization in late summer. You should no longer fertilize in autumn or the cold season, as the new growth stimulated by the additional nutrients no longer hardens sufficiently before winter. The shoots then freeze in cold winters.
Fertilizer for the tree of life
- Conifer fertilizer
- Compost
- Horn shavings
- Bluegrain
- Epsom S alt
You can get special fertilizer for conifers in stores (€8.00 on Amazon), which is well suited for thuja. It is often offered as a liquid fertilizer. This form of application is the easiest and can be distributed very evenly.
Blue grain is also often recommended. With blue grain, however, it is important to ensure that the fertilizer must be administered approximately 14 days before new growth, as it takes that long to penetrate the roots of the tree of life. Blue grain fertilization must be carried out twice a year if it is to help.
You can't go wrong if you give Thuja ripe compost or ripe manure in the spring and carefully work it lightly into the soil.
How to fertilize thuja correctly
Whatever fertilizer you give, make sure the soil is moist. In an emergency, first walk over the floor with the watering can. The fertilizer works faster on moist soil and does not burn the fine roots as quickly.
Follow dosage instructions. For blue grain you need around 50 grams per square meter.
After fertilizing, water the thuja hedge with the watering can. This means that the nutrients are released more quickly and can penetrate the soil better.
When thuja turns yellow
If the tree of life turns yellow, over-fertilization cannot be ruled out. The excess supply of nutrients causes chlorosis to develop, which causes the needles to discolor.
The risk of over-fertilization primarily occurs with artificial fertilizers that have not been dosed correctly.
These fertilizers must under no circumstances come into contact with the needles as they will burn them.
Detecting and treating magnesium deficiency
A light discoloration of the tree of life's needles often indicates a magnesium deficiency. You can get appropriate fertilizers commercially. Epsom s alt is often recommended for this. If you are not sure whether you really have a magnesium deficiency, seek advice from a specialist.
Improve the soil when planting
In the first two years after planting, you don't need to fertilize Thuja if you have prepared the soil well beforehand.
To do this, loosen it thoroughly and remove all thickenings, stones, roots, etc. Mix the potting soil with ripe compost, seasoned manure and/or horn shavings. Then the roots have sufficient nutrients available right from the start.
Peat is also suitable for improving the soil, but for ecological reasons it should only be used in emergencies.
Fertilizing with mulch covers
The best way to provide thuja with sufficient nutrients is to create a layer of mulch under the hedge. With this method you avoid over-fertilizing the tree of life. The following mulching materials are suitable:
- Lawn clippings (without seeds)
- Leaves (only he althy leaves)
- chopped thuja trimmings
- Bark mulch
- Straw
Applying a layer of mulch has the additional advantage of keeping the soil moisture constant because the water does not evaporate as quickly. The mulch also keeps weeds away and saves you a lot of work.
The mulch cover is ideally placed every year in spring and, if necessary, renewed in autumn.
Tip
Do not fertilize thuja with fresh compost or manure. Only use mature fertilizer material because, on the one hand, there is a risk of over-fertilization and, on the other hand, the roots can burn.