How many plants do I need for a 20 ft hedge?
A 20 ft hedge of arborvitae on 3 ft centers takes 7 plants; at the 4 ft spacing recommended for Green Giant it takes 6. A clipped boxwood or privet hedge at 18 in spacing takes 14 plants, and a tight dwarf boxwood edge at 12 in takes 21. Counts include a plant at each end of the row.
Plants for a 20 ft hedge by spacing
| Spacing and typical plants | Plants for 20 ft | Cost at $15 each | Cost at $40 each |
|---|---|---|---|
| 12 in: boxwood, dwarf hedge | 21 | $315 | $840 |
| 18 in: boxwood, privet | 14 | $210 | $560 |
| 24 in: yew, holly | 11 | $165 | $440 |
| 36 in: arborvitae, laurel | 7 | $105 | $280 |
| 48 in: arborvitae Green Giant, photinia | 6 | $90 | $240 |
| 72 in: large screening trees | 4 | $60 | $160 |
A 20 ft single row with a plant at each end. For a double staggered row, roughly double the count.
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Choosing and pricing a 20 ft hedge
Emerald Green arborvitae in 3 gallon pots run $25 to $45 each, so 7 of them at 3 ft spacing cost $175 to $315; 6 ft balled-and-burlapped specimens at $100 to $200 make the screen instant but push the same hedge to $700 to $1,400. Green Giant grows two to three feet a year and is spaced 4 to 6 ft, so it needs only 6 to 4 plants. Boxwood at $15 to $40 each for the 14 plants of an 18 in hedge is $210 to $560. Nurseries often discount 10 to 20 percent on orders of 7 or more, so ask. Mulch the whole 20 ft row 3 ft wide with about 8 bags of mulch.
Planting a 20 ft hedge
- Run a string line and mark each spot; the first plant sits half a spacing in from each end if the hedge must stop at a property line.
- Keep the row at least half the mature width away from a fence or wall so you can reach the back to trim.
- Dig holes twice the width of the root ball and no deeper; set the root flare at grade.
- For a dense screen fast, plant a double row with the two rows 3 ft apart and the plants staggered, which doubles the count to about 14 at 3 ft spacing.
- Water weekly through the first two summers; newly planted evergreens die of drought far more often than cold.
Common questions
How many arborvitae for a 20 foot hedge?
7 Emerald Green arborvitae at 3 ft spacing or 6 at 4 ft. For Green Giant, 6 to 4 depending on how fast you want it to close.
How many boxwoods for a 20 foot hedge?
14 at 18 in spacing for a standard clipped hedge, 11 at 24 in for larger varieties, or 21 at 12 in for a low dwarf edging.
How far apart should hedge plants be?
About two thirds of the mature width for a tight hedge: 12 to 18 in for boxwood, 3 ft for Emerald Green arborvitae, 4 to 6 ft for Green Giant, laurel, or holly. Closer spacing fills faster but crowds the plants later.