The silex or silex is becoming more and more common in native gardens. It is increasingly taking the place of the more sensitive boxwood. This has to contend with box tree wilt and box tree moths and is no longer offered in some areas. Ilex crenata is a similar looking and low maintenance alternative. The plants are just as versatile and can be pruned and shaped with similar ease. They even do well as bonsai. In the following text you can read what there is to know about the care and the plants.
Table of Contents
Characteristics
- also called Japanese holly because it comes from the Japanese islands
- Crenata means crenate, suggesting that the leaf edges are crenate
- Small-leaved Ilexart – evergreen
- Holly family
- Over 30 varieties
- Can grow up to 3 m tall uncut
- Different growth heights and widths, depending on the variety
- Grows very slowly
- Initially grew stiffly upright, later expanding
- There are male and female plants
- Flowers rather inconspicuous, cream-colored in June
- Black berries
- Be careful, the berries are poisonous!!!
Ilex crenata varieties
‘Golden Gem’ – slightly smaller yellowish leaves that turn green over time, only 80cm tall, grows wide, fits well in low rhododendron plantations
- ‘Green Luster’ – dwarf form, very dense, spherical growing variety, heavily fruiting, good for area plantings and for topiary (spherical)
- ‘Fastigiata’ – columnar holly, stiffly upright, compact habit, strong, dark green foliage, light green shoots, grows very slowly, good for group and single planting
- ‘Dark Green’ – ideal for hedges and balls, quite strong growth, likes partial shade, very hardy, tolerates pruning well
- ‘Dark Star’ – dark green, glossy foliage, grows upright, hardy, tolerant of pruning, good for hedges or as a topiary, no fruit, good for children
- ‘Blondie’ – yellow leaves in spring, leaves turn green, good for hedges or as a solitary plant
- ‘Convexa’ – Berg-Ilex – leaves similar to boxwood, dark green, slightly glossy, well suited for shady places, can reach a height of 3 to 4 m, grows in a wide funnel shape, tolerates pruning, heavy pruning promotes branching
- ‘Ellipta convex’ – compact structure, ideal topiary, narrow leaves, rather elongated, leaf margin slightly serrated, good for taller forms such as cones
- ‘Hetzii’ – Shrubby Ilex, wide habit, can reach a height of 2 m, grows very slowly, not quite frost hardy
- ‘Rotundifolia’ – Spoon Ilex, dense, wide growth, for partial shade and shade
- ‘Stokes’ – cushion holly, leaves like those of boxwood, cushion-shaped growth, can grow up to 1 m tall, slow-growing, ideal for the rock garden, semi-shady and shady
maintenance
Ilex crenata benefits from the problems that box trees have in many places, because these trees are often used as a box substitute. No box trees are dying and no Zünzler threaten the plants. In addition, numerous new varieties have come onto the market. They are ideal for hedges, area planting, edging and topiary. They are also great as garden bonsai, thanks to the special cut, the characteristic shape of a bonsai comes into its own.It is best to plant in spring so that the Ilex can grow properly by autumn. This is the only way the tree can survive the winter. Buchsilex needs enough water, not as much in summer as in autumn, but standing dry should be an exception. Fertilization is only necessary in very nutrient-poor soils. Pruning is not essential, but most of the plants will be pruned and tolerate it well. However, it is better not to cut into the old wood, as it is difficult for the plants to sprout again from there. When overwintering, it is important to ensure that the containers do not freeze, especially with potted plants. Propagation is by cuttings, but sowing is also possible. Diseases and pests are rather rare.In terms of care, the trees are not particularly demanding. Depending on the variety, they like a sunny to shady location, although bright sun and deep shade are usually not so favourable. The plant substrate should be permeable, humic and contain some nutrients. Calcareous substrates are unfavorable, slightly acidic to neutral soil is better.
Location and plant substrate
The location depends on the variety of Ilex crenata. There are those who like the sun, but most prefer a semi-shady place. There are also suitable specimens for shade, although pure shade is not quite as cheap for most of them.
- Half shade to shade
- some varieties also tolerate sun quite well
- In full shade, the growth is rather loose
- Protected from the wind, otherwise the wood can become bare
The plant substrate should be permeable, humic and contain some nutrients. Lime is not tolerated, slightly acidic soil is better. Soil that is too heavy should be loosened, and humus should be added to sandy soils, preferably bark humus.
- Acidic to neutral soils
- No lime
- Humic and nutritious
- Loosen heavy and heavily compacted soils with and
- Also mix in some peat or bark humus
plant
It is best to plant in spring so that the Ilex can grow properly until winter. This is important so that the frosts can be survived unscathed. This is not always the case with autumn planting and damage can occur. It is important to mulch the soil so that it does not dry out so quickly.
- Mulch, because the roots grow very close to the surface
- Be sure to mix in peat when planting
- For small hedges, 8 plants per linear meter are sufficient (small, in 10 cm pots)
- Water the root ball well before planting
- Planting hole should be twice as deep and wide as the existing root ball
- Mix excavated soil with organic fertilizer
- With plants balled in jute, the ball cloth can go into the planting hole as it will rot. It just needs to be untied.
- After planting, lightly step on the root edge area.
- Water well and continue to water plenty for the next few weeks!
- No waterlogging
- mulch soil
watering and fertilizing
Ilex crenata has a fairly high water requirement. The soil should always be slightly moist. Waterlogging, on the other hand, is not tolerated at all. Fertilizing is not mandatory. In nutrient-poor soils, however, help can be given. Fertilize from spring to late July.
Water especially in the fall
- Keep rather dry in summer
- Water is also needed in winter when it is dry. Water only on frost-free days. Above all, don’t forget potted plants!
- Never water directly on the flowers, as they tend to fall off afterwards
- Rainwater is best for watering. Alternatively, you can use stale tap water.
- You can fertilize, but it is not absolutely necessary.
- If fertilized, then in half concentration from spring to the end of July
- Do not fertilize afterwards so that the shoots can mature.
- Organic fertilizer is best.
- Do not fertilize in hot weather!
To cut
This Ilex does not need to be pruned, but most of the time it is. Especially when the plants have been planted to form a low hedge (bed border), they need to be cut. If a topiary is planned, a cut must also be made. The frequency of the measures depends on the growth. Some strains can be trimmed in one session, while others may require pruning throughout growth.
cutting time
- In early spring, before they sprout – ideal for hedges, because the wood then sprout evenly
- If cut in spring, second cut in August, at the latest by the end of September
- After that, do not cut again so that the new shoots can harden before the start of winter
- Never cut in sunshine – risk of burns
- Cut with a conventional hedge trimmer
- Don’t cut too deep into the old wood, it takes a long time for these spots to grow back
- It is better to cut regularly, but then little. The budding is significantly stronger from the upper shoot tips
- When cutting to shape, place the scissors evenly on the surface to be cut
- Preformed wire frames are ideal, and you can cut along the edges
hibernate
Although Ilex crenata is hardy, plants in containers in particular must be protected from freezing the ground. The trees also tolerate cold wind very poorly, which is why they should be sheltered from the wind. Planted specimens get tougher over the years. At first, they are still quite sensitive and when the temperature falls in the double-digit range, they too are happy to have some protection. If the first winters are very severe, damage can be expected.
- Frost hardy, but should not be too draughty, especially when used as a container plant
- Protect buckets from freezing
- Watering in winter is important, the plants are evergreen and also evaporate water in winter.
- Water only on frost-free days!
- Container plants can of course also be overwintered frost-free.
multiply
Propagation is usually by cuttings. The shoots for this are cut after flowering. Although rooting takes a long time, plants from cuttings develop better and are stronger than when they were sown.
- Propagation of cuttings in July or August
- It is recommended to use a rooting agent
- Rooting starts after about 4 weeks
- Rooting rate about 50 percent
- Seed must be stored in a sandy substrate for about a year before sowing
diseases and pests
The Ilex is much more resistant than the Buchs. Also, it is not threatened by so many specific diseases and pests. However, there are also fungal diseases and animal pests for Ilex crenata.
- Soil fungi – usually only occur when the soil is too wet, which the mountain holly cannot tolerate. The fungi colonize the sensitive roots. The infestation can be recognized by the black dead root tips and a white covering of the root. The rot can usually not be overlooked and you can smell it too.
- Spider mites – in warm, dry weather, can multiply rapidly in long-lasting weather conditions, suck on the underside of leaves, young leaves remain significantly smaller, leaves greenish-white speckled, translucent, leaf fall occurs
- Too high pH values lead to chlorosis.
Frequently Asked Questions
Can Ilex crenata be planted immediately after a hedge has died due to the boxwood fungus, or does the soil have to be replaced?
The boxwood fungus cannot be transferred to the ilex. The earth does not need to be replaced.
Are there varieties that don’t have the poisonous berries?
Yes, there are all-male varieties. These include Ilex crenata ‘Dark Star’ and ‘Schlossgarten’. This makes them completely harmless for gardens where children are. ‘Dark Green’ is male and has no flowers or fruits at all. ‘Schlossgarten’ has non-toxic berries.
