How Our Climate Changes the Rules
Western Oregon lawns are mostly cool-season grasses like perennial ryegrass and fine fescue. They grow hard in spring and fall, slow down in our dry summers, and compete with moss all winter. Trees get most of their pruning while dormant, and windstorm season runs from fall through early spring.
Quick rules of thumb
- Mow at 2 to 3 inches, about once a week in the growing season.
- Fertilize about four times a year: spring, late spring, early fall and late fall.
- Dethatch moss mid-March through April, not in fall.
- Most tree pruning: late fall through winter while trees are dormant.
- Storm-prep your trees in September and October.
Month by Month
January
- Trees: prime dormant pruning season for most deciduous and fruit trees.
- Storms: check trees after every windstorm for cracked or hanging limbs.
- Lawn: stay off soggy or frozen grass.
February
- Trees: finish dormant pruning before buds break.
- Lawn: moss is peaking. Plan your spring moss control.
- Property: good month to book spring stump grinding and removals.
March
- Lawn: start mowing when the grass starts growing, at 2 to 3 inches.
- Lawn: mid-March through April is the best window to dethatch moss.
- Lawn: test your soil and apply lime if it's too acidic.
April
- Lawn: spring fertilizer application; overseed thin or mossy patches.
- Lawn: aerate compacted or soggy areas.
- Trees: avoid heavy pruning while trees are leafing out.
May
- Lawn: weekly mowing; second fertilizer application late in the month.
- Shrubs: prune spring bloomers like rhododendrons and azaleas right after they flower.
- Trees: watch for pests and disease on new leaves.
June
- Lawn: mow a little higher as it warms up; water deeply and less often.
- Property: dry weather starts. Great time for power washing and roof cleaning.
- Trees: light shaping and clearance pruning only.
July
- Lawn: about 1 inch of water per week, or let it go summer-dormant. Don't fertilize a dormant lawn.
- Trees: deep water young trees every 1 to 2 weeks.
- Trees: late summer is a good time to prune maples and birches, which bleed sap less than in spring.
August
- Trees: watch for drought stress (scorched or early-dropping leaves).
- Property: dry decks and fences are ready for cleaning and sealing.
- Safety: keep dry brush and debris cleared.
September
- Lawn: best month to aerate and overseed as the rains return; fall fertilizer.
- Trees: schedule a storm-prep inspection before windstorm season.
- Property: last good dry stretch for power washing.
October
- Leaves: start fall leaf cleanups; clean gutters and downspouts.
- Trees: remove dead limbs and thin heavy ones over the roof before the big storms.
- Roof: treat moss before the wet season takes over.
November
- Lawn: final fertilizer application early in the month; keep leaves off the grass.
- Trees: dormant pruning season begins after leaf drop.
- Storms: windstorm season is here. Save our number.
December
- Storms: check trees after every storm; call us for anything hanging or leaning.
- Trees: dormant pruning continues.
- Lawn: minimal foot traffic on wet or frosty grass.
Sources
Timing guidance follows Oregon State University Extension recommendations for Western Oregon lawns, including 'Managing Moss in Lawns in Western Oregon' (EM 9176).
Let Us Handle the Calendar
- Dormant-season pruning
- Fall storm-prep inspections
- Spring and fall yard cleanups
- Summer power washing and roof cleaning