When to Plant Alliums in Divide County, ND
Ornamental alliums (Allium spp.) bridge the gap between spring and summer with their striking globe-shaped flower heads in shades of purple, violet, white, and pink. Blooming after tulips have faded, they extend the spring display well into early summer. 'Gladiator', 'Globemaster', and 'Purple Sensation' produce softball-sized heads on 18–36 inch stems, while smaller species create charming accents at border fronts. Deer and rodents shun them completely due to the characteristic onion scent. Dried seed heads provide architectural interest into fall.
Divide County, North Dakota is in USDA Zone 4a. The average last spring frost is May 15 and the first fall frost is September 20, giving you a growing season of approximately 128 days.
At an elevation of 994 feet, Divide County receives approximately 20.5 inches of rainfall annually with predominantly loam soil. Summer highs average 79°F, so choose short-season varieties of Alliums to ensure they mature before fall.
Divide County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.6
Drainage
Well Drained
Monthly Watering Guide for Alliums
Alliums needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Alliums Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2" | 0" | ❄️ Dormant |
| Apr | — | 2" | 0" | ❄️ Dormant |
| May | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Jun | 4.3" | 1.3" | 3" | 🚿 Regular watering |
| Jul | 4.3" | 1.7" | 2.6" | 🚿 Regular watering |
| Aug | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Sep | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Oct | — | 1.7" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Divide County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Alliums Planting Timeline — Divide County, ND
Alliums Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Bloom | September 20 | Sep 20 – Oct 11 |
| Fall Sowing | August 9 | Aug 9 – Aug 23 |
Plant 5" deep · 7" apart · Rows 8" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | — |
| July | — |
| August | Fall Sowing |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
28–42 days
🧪 Soil pH
Needs 5.5–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 4a
📆 Growing Season
128 days in Divide County
Growing Tips for Divide County
Plant bulbs in fall, 3–4 times as deep as the bulb diameter (typically 4–6 inches for large types, 3 inches for small species). Space 6–8 inches apart for standard cultivars. Foliage often looks untidy as it dies back before bloom — plant around perennials that will conceal the yellowing leaves. Excellent drainage is essential; alliums rot in wet soils. Leave bulbs in place for naturalization; divide every 3–4 years when clusters become congested. Deadhead spent globes or leave for ornamental seedheads and self-sowing.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Alliums in Other Locations
Frequently Asked Questions
When should I plant Alliums in Divide County, ND?
Divide County is in Zone 4a with an average last frost of May 15. Plan your Alliums planting based on this frost date — see the calendar above for exact timing.
What planting zone is Divide County, ND?
Divide County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 15 and first fall frost is September 20.
Your Divide County Garden Planner — Free
A 22-page printable planner built for Divide County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.