Both with classic trellises and special forms, the question of the best wood will eventually come up. FassadenGrün recommends Robinia wood for high-quality trellis with a very long service life because then the contact points of the spar and battens do not rot. Please ask us for sources of supply! Alternatively, oak, chestnut, larch and ultimately also all conifers come into question, but then with a coat of paint or impregnation. Robinia wood does not need paint, but can be, for example, with "Swedish red" or "Ovolin egg tempera". Please also use our overview of the topic "Wooden Trellis".
When using Robinia wood, please note: Nailing into this "rock hard" wood is virtually impossible. Each connection must be pre-drilled and screwed. This also applies to FassadenGrün's espalier screws and staple nails.
The high resistance against plant and animal pests is only reached by the heartwood, which accounts for (only) about 70-80% of the trunk. Square profiles are made of straight grown plantation wood, it should also be "air-dry", then it does not distort and can be attached to only 2 points. A slight distortion with slight curvatures, etc., must also be no blemish, but can give the trellis a natural touch. Laths that are attached to at least three points and thus necessarily kept straight, can also dry on the façade.
In the soil Robinia wood can probably be installed in larger cross sections (over 15 cm) as unpeeled or milled round trunk even without prior drying. Often halved or quartered round logs are used, e.g., As for fencing, coupling, etc.. The wood cross-section is better utilized here, and the high sawmill costs are not incurred. The profiles should be correspondingly strong in order to achieve a suitability for the intended use. In vineyards they stand for about 25 to 30 years, then the entire construction with plant is ploughed and newly planted.
In many areas there are Robinia populations, sometimes limited to forest and road edges. It is worthwhile to ask the local forestry authorities if large quantities of logs or peeled logs are needed. If the cutting can be avoided, it should be avoided, since it causes enormous costs in Germany. Air-dried square woods for trellises, on the other hand, mostly come from Hungary, Serbia, Slovakia or the Ukraine, because there are plantations with straight trunks.
Important to know: Robinia wood is poisonous, and the safely encapsulated "Robinetin", acting as impregnation in dry wood, can be released when processing the wood (sawing, drilling, sanding) and can lead to nausea. The "sawing" of Robinia is therefore carried out in the sawmill by wet cutting or with safe extraction. Also laths for trellises should be sawed outdoors or in ventilated areas.
Known for its high-quality, it was nevertheless avoided by carpenters: the wood of the Robinia (Robinia pseudoacacia), also known as "False Acacia" ("acacia wood"). Due to its extreme hardness and toughness, it is difficult to process and tends to twist. So it was used only in mining, for example, to supported tunnels. After all, Robinia wood is sturdier than oak! Meanwhile, Robinia is used as a teak replacement mainly for garden furniture, playground equipment and hydraulic engineering.