Sizes and densities
Which size,
how many per m²
A bulb’s size is its circumference in centimetres. It governs how strong the first flowering will be, and it is where two quotes at the same price part company. Density decides the effect: full, open, or naturalised.
How to read a bulb size
A size is written as 12/14: the bulb measures between 12 and 14 centimetres in circumference. The higher the number, the larger the bulb and the stronger the first year’s flower. A 16/18 daffodil does not give the same first season as a 12/14, for a price per thousand that can be close.
That is why a properly written specification requires delivery fifteen days before the works, so the size can be checked before planting. The sizes below are those Natura Loci actually supplies, taken from the autumn 2026 price list.
Large spring bulbs
| Species | Size | Density | Source |
|---|---|---|---|
| Garden tulips Triumph, Darwin hybrid, Fosteriana, double, parrot, viridiflora, lily-flowered, fringed |
12/14 | 60 to 100/m² in a full bed | Trade standard |
| Botanical tulips clusiana and related species |
6/8 | 100 to 150/m² | Trade standard |
| Trumpet and large-cupped daffodils | 14/16 to 16/18 | 40/m² for a natural, open effect 40 to 60/m² in a bed |
Natura Loci practice Trade standard |
| Double daffodils | 14/16 to 16/18 | 40 to 60/m² | Trade standard |
| Jonquilla, triandrus and cyclamineus daffodils small scented flowers |
12/14 to 14/16 | 60 to 80/m² | Trade standard |
| Hyacinths | 17/18 prepared 19/20 · multiflora 22/24 |
40 to 50/m² | Trade standard |
| Crown imperial fritillaries | 20/22 to 24/26 | 5 to 7/m² | Trade standard |
| Giant alliums Globemaster, giganteum |
20/22 | 15 to 25/m² | Trade standard |
| Allium aflatunense “Purple Sensation” | 10/12 to 12/14 | 30 to 50/m² | Trade standard |
Small bulbs and bulbs for naturalising
| Species | Size | Density | Source |
|---|---|---|---|
| Large-flowered crocus | 7/8 to 9/10 | 100 to 150/m² | Trade standard |
| Botanical crocus tommasinianus, chrysanthus |
5/6 | 150 to 200/m² | Trade standard |
| Muscari | 8/10 to 9/10 | 100 to 150/m² | Trade standard |
| Scilla siberica | 8/10 | 200/m² in an intensive band | Natura Loci practice |
| Hyacinthoides hispanica Spanish bluebell |
8/10 | 100 to 150/m² | Trade standard |
| Snowdrops Galanthus |
5/6 to 8/10 | 150 to 250/m² | Trade standard |
| Eranthis and chionodoxa | 5/6 | 150 to 250/m² | Trade standard |
| Puschkinia | 6/8 | 100 to 150/m² | Trade standard |
| Allium sphaerocephalon | 5/6 | 50 to 100/m² | Trade standard |
| Snake’s head fritillary meleagris |
5/6 to 7/8 | 50 to 100/m² | Trade standard |
| Camassia leichtlinii |
14/16 | 20 to 40/m² | Trade standard |
| Naturalised stinzen bulbs in grass | — | up to 250/m² depending on the project | Natura Loci practice |
Densities marked “Natura Loci practice” are the figures we use in our own quotations. Those marked “trade standard” are common reference ranges, to be tightened according to the site, the effect wanted and the budget.
Densities by type of planting
These five densities cover the large majority of projects. They come from our quotations, not from a theoretical table.
| Planting | Density |
|---|---|
| Full mix in a border or flower band | 100/m² |
| Natural, open effect daffodils in grass, drifts |
40/m² |
| Wildflower meadow over a sown bed | 75 to 80/m² 100/m² when planted full |
| Cutting-flower bands in cemeteries | 60/m² in spring 30 to 35/m² for summer flowers |
| Planters, pots and urns | 200/m² |
From square metres to the quantity ordered
Area multiplied by density gives the quantity, rounded up to the next thousand, since the mixes are packed in thousands of bulbs. Three bands of eleven metres by one metre at sixty bulbs per square metre come to 1,980 bulbs, so 2,000.
In a public tender schedule, the area and the density are repeated in brackets after the item description: “(33 m², 60 bulbs/m²)”. The tenderer then prices against a verifiable basis, and the authority can recalculate the stated quantity.