When to Plant Lilies in Benton County, OR
Lilies (Lilium spp.) are among the most impressive summer-blooming bulbs, delivering bold, upward- or outward-facing trumpet blooms on tall stems from June through August. Asiatic hybrids are the most cold-hardy, earliest to bloom, and easiest to grow; Oriental hybrids bloom later with intensely fragrant, larger flowers. Orienpet (OT) hybrids combine the hardiness of Asiatics with the fragrance and size of Orientals. True lilies (not to be confused with daylilies, which are Hemerocallis) form scaly bulbs that persist and multiply underground, returning reliably each year with increasingly large clumps.
Benton County, Oregon is in USDA Zone 8b. The average last spring frost is April 14 and the first fall frost is October 30, giving you a growing season of approximately 199 days.
At an elevation of 97 feet, Benton County receives approximately 53.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Lilies during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Lilies root diseases.
Benton County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Lilies Planting Timeline — Benton County, OR
Lilies Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 7 | Apr 7 – Apr 21 |
| Bloom | June 16 | Jun 16 – Oct 6 |
Plant 5" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | — |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
70–120 days
🧪 Soil pH
Needs 6–6.5 · Your soil: N/A
🗺️ USDA Zone
Zone 8b
📆 Growing Season
199 days in Benton County
Growing Tips for Benton County
Plant bulbs in fall (preferred, September–October) or spring, setting them 3 times their diameter deep (typically 4–6 inches) with the pointed end up. Lilies need excellent drainage — they will rot in wet or heavy clay soils. Site with full sun on stems and blooms but cool, shaded soil at the base (ground cover or shallow-rooted annuals at their feet is ideal). Remove spent blooms but leave stems and foliage until they yellow naturally, as the bulb needs the foliage to photosynthesize and rebuild energy stores. Red lily beetle is a serious pest in the Northeast and Pacific Northwest; inspect plants regularly and hand-pick adults and larvae. Never plant Oriental or Asiatic lilies near cats — all Lilium species are highly toxic to cats. Year 2+ bulbs produce the most stems and largest blooms.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Lilies in Other Locations
Frequently Asked Questions
When should I plant Lilies in Benton County, OR?
Benton County is in Zone 8b with an average last frost of April 14. Plan your Lilies planting based on this frost date — see the calendar above for exact timing.
What planting zone is Benton County, OR?
Benton County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 14 and first fall frost is October 30.
Your Benton County Garden Planner — Free
A 22-page printable planner built for Benton County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.