If you are looking for landscaping in Kelso, WA, the river and the hills both get a say in your yard. Kelso was platted in 1884, decades before Longview existed across the Cowlitz, and became the Cowlitz County seat in 1922. Its flats sit behind levees on the Cowlitz and the channelized Coweeman, and its east side climbs into hills where Kelso learned in 1998 what saturated ground can do.
Bogar Landscaping is about 20 minutes south on I-5 in Woodland, close enough to treat Kelso as home turf. We work in North, South and West Kelso, up Old Kelso Hill and Hilltop, along the Coweeman near Tam O'Shanter Park, and out in Rose Valley and Carrolls. Most jobs here mix drainage with cleanup: older lots that hold water, slopes that need care, and fence lines lost to blackberry.
Kelso at the Three Rivers: Levees, Floodplain and Groundwater
Three rivers meet at Kelso: the Cowlitz, the Coweeman and the Columbia. The Coweeman is channelized and diked through town, and the federal levee on the Cowlitz begins north of Fishers Lane and runs toward Longview. Parts of the city, including Three Rivers Golf Course, sit on volcanic ash dredged out of the Cowlitz after the 1980 eruption of Mount St. Helens.
That sediment is still in the river. During the December 2025 storms, which became federal disaster DR-4906 for Cowlitz County, Kelso's public works manager said the sediment raises the groundwater table a little. Higher river, higher water under your lawn.
The soil adds to it. Kelso silt loam, common on the terraces here, has a silty clay loam subsoil, is strongly acid and holds a perched water table 2 to 3 feet down from December through March. In practice:
- Low yards on the flats stay wet well after the rain stops, because water perches on the subsoil.
- Acid soil and wet winters favor moss over grass, and WSU lists both as moss drivers.
- Drains need an outlet that stays lower than the yard even when the rivers run high, so we check the route before digging.
Kelso's Hillsides and the Aldercrest-Banyon Slide
Aldercrest was an 80-acre neighborhood in east Kelso built from 1973 to 1979 on top of an old landslide. In February 1998, after three and a half years of above-average rain, the ground started moving again. By June, 54 homes were inside the active slide; the city eventually condemned 137 homes, damage passed $70 million, and a presidential disaster declaration followed on October 16, 1998.
You do not need to live near Aldercrest for the lesson to apply. Soil samples on Kelso's hills include Hazeldell gravelly silt loam on 30 to 65 percent slopes, and neighborhood names like Old Kelso Hill and Hilltop tell you where the grades are. On sloped Kelso lots we follow a few rules:
- Keep water off the slope. Downspouts, sump lines and driveway runoff go into solid pipe to a stable outlet, never onto a bank or into a trench at the top of one.
- Fix leaks fast. A broken irrigation line can feed a hillside for months unnoticed.
- Do not pile fill at the top of a slope. Extra soil, rock or yard waste adds weight where it does the most harm.
- Drain every wall. Drain rock, filter fabric and perforated pipe go behind any block wall we build.
If you see new cracks in the ground, doors that suddenly stick or a wall starting to lean, call the City of Kelso or Cowlitz County and a geotechnical engineer first.
Older Kelso Homes, Neighborhoods, Rose Valley and Carrolls
Kelso's housing runs older than Longview's: half of the city's homes were built in 1961 or earlier, according to American Community Survey data summarized by City-Stats. Older lots can come with mature trees, buried and forgotten drain lines, beds that have not been rebuilt in decades, and back corners where Himalayan blackberry has taken over. Blackberry is a Class C noxious weed in Washington, and roots left in the ground resprout.
We work across the city's neighborhoods, including North, South, East and West Kelso, Butler Acres, Davis Terrace, Mt. Pleasant and the streets near Tam O'Shanter Park, a 38-acre park on the Coweeman.
Two unincorporated communities just outside town also fall under the Kelso ZIP code:
- Rose Valley sits southeast of Kelso at about 351 feet, reached from I-5 exit 36 by way of Old Pacific Highway and Rose Valley Road. Expect larger rural parcels with slopes, gravel drives and brush.
- Carrolls lies south of Kelso on Old Pacific Highway at the same exit, on low ground near the rivers at about 69 feet, so yards sit lower and flatter.
Both are in unincorporated Cowlitz County, so permits run through the county rather than the City of Kelso.
