Nursery plants are graded and traded according to Plantestandard and Kvalitetsstandard. Here's how to read girth, bare-root/root-balled/container, and delivery sizes.
Introduction
Plants are bought using standardised terms, so you know what you are getting. Grading and bundling of bare-root, root-balled and container plants follow the rules of the Danish Nurserymen's Association (Plantestandard 2002), and the quality of nursery trees is described in Kvalitetsstandard 2019.
Trunk girth — the trade size for trees
The trade size of nursery trees is measured as trunk girth in cm at 1 m above the root collar (Quality Standard 2019):
- 01Standard trees are supplied from 14–16 cm girth.
- 02Standard trees are supplied from a 12–14 cm trunk girth.
- 03Typical ranges: 14–16 / 16–18 / 18–20 / 20–25 / 25–30 cm.
- 04Root-ball size follows a table based on trunk girth.
Delivery forms
- 01Bare-root plants (barrod): supplied without soil around the roots. Cheap, but only in the winter half-year (dormancy) and mainly deciduous species — the roots must not dry out.
- 02Clump plants: delivered with a soil ball around the roots, held by net or bag. Used for larger trees and evergreens.
- 03Container plants: grown in pots and supplied with the entire root ball. Can be planted year-round if watered.
Plant types
- 01Solitary trees and shrubs: freestanding ornamental plants where form and size are decisive.
- 02Avenue trees: trees grown with continuous straight trunks for roads, avenues and squares.
- 03Hedge plants: supplied in many small plants for row planting (see 'Plant spacing and bonding').
- 04Ground cover and climbing plants: cover soil or surfaces; mostly delivered in containers.
- 05Perennials: perennial herbaceous plants, typically in smaller containers.
Lump and container sizes
Quality Standard 2019 ties the rootball size to the tree's commercial size: the larger the stem girth, the larger and heavier the rootball — the standard specifies the associated rootball dimensions in a table. The principle is that the rootball must contain enough root for the tree to establish itself. Container plants are instead specified in pot volume (litres); a larger pot contains a larger root system. Always check rootball/root mass against the order at delivery.
| Plant category | Typical delivery form | Guidance volume |
|---|---|---|
| Stalwarts | Container | 1–3 litre |
| Ground cover, small shrubs | Container | 2–5 litre |
| Larger shrub / smaller solitary | Container or lump | 5–15 liter |
| Trees 14–20 cm circumference | Clump (open ground) or large container | Lump measure cf. Quality standard 2019 — grows with volume |
| Large solitary trees 20–30+ cm | Wire bundle / bag, often crane lift | Lump size per standard table |
Container sizes are guideline trade conventions. The binding clump/pot volumes per stem circumference are tabulated in Quality Standard 2019 and must be read there at receipt inspection — a clump smaller than the ordered size contains too little root and gives poor establishment. Look up the exact size in the standard rather than guessing.
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