Blehnum Is Not A Fern For Everyone. Derbyanka. Home Care. Photo

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Blehnum Is Not A Fern For Everyone. Derbyanka. Home Care. Photo
Blehnum Is Not A Fern For Everyone. Derbyanka. Home Care. Photo

Video: Blehnum Is Not A Fern For Everyone. Derbyanka. Home Care. Photo

Video: Blehnum Is Not A Fern For Everyone. Derbyanka. Home Care. Photo
Video: Growing Maidenhair Ferns & Moisture Loving Houseplants - Adiantum 2023, December

One of the most original types of indoor ferns, blehnum, is rightfully considered one of the most capricious. Its thermophilicity and humidity requirements have made this relict plant a true legend. Blehnum, or the derbyanka in the room, is not a fern for everyone, but it is amazingly beautiful. Quite large sizes and remotely resembling palm frond leaves will easily overshadow any other decorative deciduous plant in your interior.

Derbyanka humpbacked, or Blechnum humpbacked (Blechnum gibbum)
Derbyanka humpbacked, or Blechnum humpbacked (Blechnum gibbum)


  • Blehnum is almost the most capricious of the ferns
  • Blehnum care at home
  • Blehnum transplant and substrate
  • Blehnum diseases and pests
  • Reproduction of Blehnum

Blehnum is almost the most capricious of the ferns

Ferns are plants that are easily recognizable not only for their appearance, but also for their unique character. Moisture-loving, loving stable conditions and high-quality care, these ancient inhabitants of interiors, however, are by no means uniform in their capriciousness.

Among the ferns, there are also plants that are suitable even for beginners, and species that only experienced flower growers can grow. Derbyanka is one of the latter. It is often referred to as one of the most "serious" or demanding ferns introduced into indoor culture. And this plant fully justifies its reputation.

The botanical name derbyanok or palm ferns, as they like to call these delicate aristocrats we - blehnumy (Blechnum). They represent the family of the same name Derbyankov (Blechnaceae). The appearance of these ferns is in many ways more reminiscent of palm trees, and not of their fellows. After all, long feathery leaves are so similar in cross-section to narrow symmetrical lobes of pinnate palm trees, but only in miniature and from a distance. Although leaf development and growth are typical of ferns, the older the plant gets, the more it resembles a palm tree.

Derbyanki are slow-growing ferns. With a height of 50 cm to 1 m, this species cannot be ranked among the most compact of indoor relics. The leaves are collected in strict rosettes, rather long, they look both impressive and airy due to the gaps between the lobes, and not their dense arrangement. Petioles are shortened or almost invisible. In addition, the leaves, with their slight drooping, further emphasize the grace and originality of the fern, which manifests itself with age.

The rhizomes are thick, the gradually modified rhizome takes on a trunk-like shape and rises in height up to half a meter, which makes it look like palm trees. Derbyanki rarely bloom and do not regularly give spores even in ideal conditions for them, so getting the opportunity to grow ferns from spores is a great success. Sporangia are located almost along the edge of the segments, on the underside of the leaves.

In nature, the species diversity of Blehnum is measured by several hundred plants. In room culture, everything is much simpler: the most common humpback blechnum (Blechnum gibbum). The plant is sometimes sold under the name of another garden fern in this family, Blechnum spicant. But the spiky derbyanka is an open ground plant, you should not confuse the two species with each other, because they differ both in nature and in the scope of use.

The "greenhouse" species of Blechnum are considered very rare - olive-green broad-leaved Brazilian Blechnum (Blechnum brasiliense); Blechnum serrulatum (Blechnum serrulatum) with charming lobes and a compact, dark-leafed, almost black petiole species of Blechnum moorei.

Fern Derbyanka, or Blechnum (Blechnum)
Fern Derbyanka, or Blechnum (Blechnum)

Blehnum care at home

Blehnums feel great in greenhouses and winter gardens, flower showcases. These are very capricious plants, famous for their warmth and moisture-loving nature. But even if the derbyanka is not suitable for beginners, experienced flower growers can experiment with this magnificent fern in indoor conditions. This plant is for those who love the difficulties and difficult nature of their pets.

Lighting for Blehnum

Derbyanki feel great only in "medium" lighting - not too bright, but not too shaded. Sunny and even absent-mindedly bright areas will not suit them, but all semi-shady locations will be an excellent refuge.

A lover of partial shade blehnum feels good not on the windowsills, but not far from them in the interior, which allows using the Derbyanka as an exclusive decoration of rooms, a noble, architectural, strictly aristocratic accent.

Comfortable temperature setting for blechnum

Without a constant warm environment in the cultivation of Blehnum, success cannot be achieved, but the fern combines its thermophilicity with a dislike of heat.

This houseplant is very demanding on temperatures and will not tolerate even light coolness. The minimum permissible air temperature for this fern is -16 degrees, and the plant will withstand such indicators only in winter. But even in the warm season, the Blehnums prefer restrained conditions, poorly tolerating hot temperatures above 25 degrees. The closer the temperature in summer is to 20-23 degrees, and in winter - to 18 degrees, the better. It is necessary to control not only the air temperature, but also the temperature of the soil.

One of the most "difficult" features of this fern is the love of fresh air. Blechnums need neat but constant ventilation. The plant will prefer to spend summer in the fresh air, but only if it is protected there from the heat and will continue to receive regular care.

Blechnums are extremely sensitive to drafts and any changes in air temperature. Plants need to be protected during airing, and even from active "passages" around the room, not to mention air conditioners or heating devices. Particular attention should be paid to protecting the bottom of the pot: cooling it can lead to the death of the plant even faster than drought. Therefore, it is better to place blechnums on supports, protecting from possible hypothermia of floor materials or furniture.

Watering and air humidity for Blehnum

Blehnum cannot be grown without constant high soil moisture, but the plant does not like excessive moisture either. The balance between comfortable humidity and waterlogging can be observed only by carefully checking the condition of the substrate and studying the reaction of the plant itself. The roots of this fern should be in a stably moist environment, drying out is destructive for them.

Water for blehnums will also have to be carefully selected: this type of ferns cannot stand watering with non-soft water, even an insignificant lime content can destroy the plant. In addition to settling, you will have to take care of the water temperature: it should be several degrees higher than the temperature of the earthy coma.

But even the Blechnum requirements for stable heat overshadows their need for air humidity. Indicators for this fern should be not just high, but very high, from 75%. And at the same time, the plant cannot be sprayed (even rare these procedures will lead to a deplorable wai appearance), so the task of creating a comfortable environment is not so simple.

Devices humidifiers, domestic or industrial, will cope with the task, as well as the placement of plants in the florarium, proximity to indoor fountains and aquariums. You can also achieve a comfortable environment for the fern by growing the pots by immersing them in a large outer container filled with expanded clay, wet pebbles, peat, hydrogel, etc.

Derbyanka humpbacked, or Blechnum humpbacked (Blechnum gibbum)
Derbyanka humpbacked, or Blechnum humpbacked (Blechnum gibbum)

Top dressing for Derbyanka

This fern needs regular feeding. Fertilizers for it are applied at a frequency of 1 time in 2 weeks. For blehnum, special fertilizer mixtures for ferns or at least fertilizers for decorative deciduous crops are more suitable. The dosage recommended by the manufacturer, even when using special fertilizers for ferns, is halved.

Top dressing for Blehnum is completely stopped for the period from October to February. After transplanting, top dressing is not carried out from 3 months to six months, often introducing them only in the second year after transferring to a new container. It is also worth doing with a newly acquired plant.

Pruning on Derbyanki

No matter how beautiful blechnum is, without regular cleaning it will look sloppy and neglected. In this fern, the lower old leaves lie down, turn yellow and dry, but do not fall off on their own. They need to be cut at the very base of the stem, without leaving hemp, removing as soon as they begin to greatly spoil the decorative effect of the rosettes. Healthy and young fronds should not be touched, even if they are "knocked out" of the common crown of old plants.

Fern Derbyanka, or Blechnum (Blechnum)
Fern Derbyanka, or Blechnum (Blechnum)

Blehnum transplant and substrate

Changing the container is always very stressful for this capricious fern who loves a stable environment. Therefore, blehnums are not transplanted annually, but only when there is a real need to change the capacity and substrate, the plant simply has nowhere to develop further. This fern prefers emergency rather than routine transplants.

Changing pots and substrate can be done in spring and summer at any convenient time, which expands the ability to avoid the transplant procedure longer.

Even the soil for this fern must be specific. Derbyanki need a loose, coarse substrate with a high humus content. A soil reaction for Blehnum is preferred with a pH of about 5.0. When self-mixing, equal parts of peat and humus earth are usually combined, taken with half the amount of sand and chopped moss.

This procedure itself should be done as carefully as possible. A few days before transplanting, the fern is watered abundantly. When transplanting, contact with the roots of the fern should be minimized by simply rolling over the plant and slightly cleaning the top contaminated soil layer, but acting very carefully.

After transplanting, Blehnums need careful watering, but very high humidity. It is better not to feed them until the plant uses the supply of nutrients from the soil. This fern can do without feeding even for 5-6 months. Only after that, fertilizing is introduced into the care program with the usual frequency.

The containers for blehnum should not be cramped: usually, when transplanting, the size of the pots is increased not by 2-3, but by 4-5 cm, so that the roots have where to develop, but they should not be too spacious either. The choice of not too large, but still large pots allows not only to create the most comfortable environment for growth and development, but also to avoid frequent transplants.

Blehnum diseases and pests

On blechnums, pests are quite frequent guests. The slightest deviation from optimal care is enough, as this fern becomes vulnerable to scale insects, spider mites, thrips, felts, aphids. It is better to deal with them immediately with insecticides.

Common growing problems:

  • drying of the tips of the leaves in very dry air, near heating appliances, in drafts;
  • depressed appearance with a lack of fresh air;
  • yellowing of leaves at too hot temperatures;
  • the appearance of brown spots on the leaves in the absence of ventilation and heat;
  • growth retardation at low humidity, improper selection of the substrate;
  • translucency, lethargy, blanching of leaves under too bright light;
  • dull leaves with yellow or brown tips, combined with growth arrest, when the wrong choice of capacity, poor feeding;
  • curling of leaves after yellowing and browning, wilting or dying off of young leaves in the cold, when watered with hard or cold water.

Reproduction of Blehnum

This fern is propagated mainly by spores. Spores are shaken off onto the surface of a moistened, leveled substrate in wide, but shallow containers, and then the crops must be covered with film or glass. They are germinated in a moist and acidic substrate (peat or peat-sand mixture), at a stable temperature of 22 degrees Celsius, with lower heating and in full shade until the first shoots appear.

The emergence of seedlings can be expected for several months. Young plants need soft lighting and extremely stable conditions, they are grown in greenhouses. Thinning is carried out as soon as the plants get stronger, leaving no more than one plant for every 2-3 cm of soil. They can be dived into separate containers after the plants grow up to five centimeters in height.

Separation of blehnums is rarely resorted to, since the fern painfully tolerates even an ordinary transplant. But if the plant has grown too much or there is no other option, if you like to experiment, then when transplanting, you can try to divide the rhizome. This procedure can only be carried out on ferns with at least 4 strong growth points.

Indoor blechnums are divided into large sections with one (or better 2 - 3) strong growth point and powerful roots, working with a sharp knife, immediately processing the cuts. Plants will need long-term adaptation, careful and thorough care.