KNOWLEDGE
Specifying plants, done properly
Drawn from The Glenmore Specification — our guide to specifying plants for commercial landscaping: sizes, seasons and good practice.
Sizes & specification
Pot sizes explained
Pot size and plant size travel together — a bigger pot buys a bigger, older plant.
- 9cm — young herbaceous, 5–9/m²
- 2–3L — established herbaceous, small shrubs
- 5L — shrubs 40–60cm with a formed framework
- 10L — specimen shrubs, instant presence
- 15–25L — large shrubs & light standards
- 45–65L+ — standard & selected trees
Heights, girths & rootballs
Heights are measured from soil level to the top of growth, quoted as a grown range. Tree girth is the stem circumference at 1m above ground — the industry standard, because girth tracks root volume and establishment better than height.
- Whip — 0.6–0.9m
- Feathered — 1.5–2.5m
- Standard — girth 8–10cm
- Selected — 10–12cm
- Heavy std — 12–16cm
- Semi-mature — 20cm+
Tree forms & topiary
Specify the form and the clear stem, and every tender prices the same tree.
- Feathered — branched to the base
- Standard — clear stem 1.8–2m
- Half-standard — clear stem c.1.2m
- Multi-stem — several stems from base
- Pleached — trained frame, clear stem
Planting
Planting step by step
Most establishment failures are planting failures. Seven steps, done properly, cover almost everything.
01 · Dig the pit
Square, 1.5× the rootball width and no deeper than its height.
02 · Water the plant
Soak the rootball thoroughly before it goes in the ground.
03 · Free the roots
Remove the pot; tease out any circling roots.
04 · Position
Root collar at finished level, resting on firm ground.
05 · Backfill
Return the native soil around the rootball.
06 · Firm in
Firm in layers to close air pockets — don't compact.
07 · Water in
A full soak to settle soil around the roots.
Then walk away rarely
Check ties, water and the weed circle through the first two seasons.
Good practice
Plant care after planting
The defects period is won in the first two seasons. Deep, infrequent soaks beat daily sprinkles. Keep a 1m weed-free circle around every tree and shrub — grass is the strongest competitor young stock faces. Formative pruning in the dormant season; feed only where growth or colour says so.
Water & establishment
Budget trees 25–50 litres per visit, weekly in dry spells, for two seasons; shrub beds 15–25 l/m². Watering bags or a soil basin put water where the roots are. When water is short: trees first, evergreens second, herbaceous last.
Growing media & peat-free
Our mixes blend bark, wood fibre, coir and controlled-release nutrition — peat-reduced as standard, peat-free across more of the range every year. Peat-free rootballs hold less reserve water and nutrient, so plan first-season feeding and closer watering checks into the handover.
Specifying for biodiversity net gain
A mixed native hedge scores as habitat creation; 5–8 species mixes beat monocultures; UK-provenance natives support more invertebrates; layered canopy + shrub + ground structure beats any single layer. Send the habitat plan and condition wording — we'll price a compliant, available planting list against it.
The Glenmore Specification
The full guide — around 250 species and cultivars illustrated, size tables, availability calendar and good practice, in one book.