Trees, shrubs and perennial grasses that stand all year, read alive in the cool season and as bleached architecture in summer. Budget 10–15.
Perennial herbs and dwarf-shrubs that flush and retreat with the seasons. Budget 6–12.
The annual flora that appears after rain, performs, and vanishes — where the richness lives. Tagged by relay pulse where the data supports it; procured as one composed mix. Budget 30 minimum — the floor the engine enforces.
The year as scored by the scheme you have composed. Timing shifts by region — the wetter south-west and the winter-rain north do not share the Najd calendar.
Spine and support as nursery stock. Centres lead: density is set from the centres (square grid) and rounded up to whole plants per m² (the round-up carries a margin for error); where a source states a density lower than its centres give, the centres win. Rates come from the Red Sea Airport schedule (P11854) adjusted to its centres; species not in it are sized by mature height from the SGI Native Plants Companion; species with neither are flagged. Each row carries a National Plant Specification (NPS) line: shrubs by container, height band, habit and breaks; herbaceous plants and grasses by container, minimum spread and buds; trees by form, calliper (Riyadh practice; girth comparison in the reference table below), height, clear stem and root protection. Trees are placed individually from the plan. The ephemeral carpet is seed-broadcast and stays out of this table.
Ephemeral carpet · seed mix E1
Calliper and girth: reference table
Calliper (governs, Riyadh practice): trunk diameter in mm, measured 150 mm above ground, or 300 mm above ground where the calliper exceeds 100 mm (ANSI Z60.1); with slot callipers, average the smallest and largest readings. Girth (UK NPS): trunk circumference in cm, measured 1 m above ground. Calliper ≈ girth × 10 ÷ π. Because the two are measured at different heights and trunks taper and are rarely round, the conversion is approximate: for reference only, not for acceptance.
| NPS girth (cm) | NPS form | ≈ Calliper (mm) | ≈ Calliper (in) |
|---|---|---|---|
| 4-6 | Standard (Half) | 13–19 | 0.5–0.8 |
| 5-6 | Standard (Extra light) | 16–19 | 0.6–0.8 |
| 6-8 | Standard (Light) / Feather | 19–25 | 0.8–1.0 |
| 8-10 | Standard (Standard) | 25–32 | 1.0–1.3 |
| 10-12 | Standard (Selected) | 32–38 | 1.3–1.5 |
| 12-14 | Standard (Heavy) | 38–45 | 1.5–1.8 |
| 14-16 | Standard (Extra heavy) / Multi-stem | 45–51 | 1.8–2.0 |
| 16-18 | Standard | 51–57 | 2.0–2.3 |
| 18-20 | Standard | 57–64 | 2.3–2.5 |
| 20-25 | Standard | 64–80 | 2.5–3.1 |
| 25-30 | Semi-mature | 80–95 | 3.1–3.8 |
| 30-35 | Semi-mature | 95–111 | 3.8–4.4 |
| 35-40 | Semi-mature | 111–127 | 4.4–5.0 |
| 40-45 | Semi-mature | 127–143 | 5.0–5.6 |
| 45-50 | Semi-mature | 143–159 | 5.6–6.3 |
| 50-60 | Semi-mature | 159–191 | 6.3–7.5 |
| 60-70 | Semi-mature | 191–223 | 7.5–8.8 |
| 70-80 | Semi-mature | 223–255 | 8.8–10.0 |