Chrysanthemum (Garden Mum) in Zone 5a & 5b
Chrysanthemum x morifolium
Yes, chrysanthemum (garden mum) grows in zones 5a and 5b and comes back each year. Start seeds indoors Mar 15–Mar 22 and plant out May 24–May 31.
When to plant chrysanthemum (garden mum) in zone 5b
Zones 5a and 5b share the same average frost dates, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. It needs a head start most zones can't give it by direct-sowing alone.
| Start indoors | Mar 15–Mar 22 |
|---|---|
| Direct sow / transplant outside | May 24–May 31 |
| Estimated bloom | First real harvest the season after planting |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-3 ft.
Before you plant: Chrysanthemum (garden mum) has a winter-hardiness note for zone 5b. See the details below.
Plant alongside it in zone 5b
These go outside within two weeks of chrysanthemum (garden mum) in zone 5b, so one planting day can cover them.
- NasturtiumMay 17–May 24
- MarigoldMay 17–May 24
- Angelonia (Summer Snapdragon)May 24–May 31
- Bee BalmMay 24–May 31
- Black-Eyed Susan VineMay 24–May 31
- Cleome (Spider Flower)May 24–May 31
Garden mums are sold in bloom in September and treated as decoration. NC State Extension lists them as perennial in zones 5 through 9, which means most of the country is throwing away a plant that would come back.
How chrysanthemum (garden mum) fits zone 5's season
Zone 5b's frost-free window runs about 148 days, from May 10 to October 5. Chrysanthemum (garden mum) takes about 1 growing season to reach full flowering, so what matters here is how many of these seasons it gets, not whether one is long enough.
Chrysanthemum (garden mum) is hardy in zones 5-9, so in zone 5b it stays in the ground through winter and comes back rather than being replanted. Allow about 1.5 ft of spread at maturity.
Chrysanthemum (Garden Mum) planting windows in every zone
Zone 5b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Bloom |
|---|---|---|---|
| 5a & 5b (your zone) | Mar 15–Mar 22 | May 24–May 31 | First real harvest the season after planting |
| 6a & 6b | Feb 28–Mar 7 | May 9–May 16 | First real harvest the season after planting |
| 7a & 7b | Feb 13–Feb 20 | Apr 24–May 1 | First real harvest the season after planting |
| 8a & 8b | Jan 28–Feb 4 | Apr 8–Apr 15 | First real harvest the season after planting |
| 9a & 9b | Dec 21–Dec 28 | Mar 1–Mar 8 | First real harvest the season after planting |
Good companions
No well-established companions for chrysanthemum (garden mum).
Where to buy chrysanthemum seeds
True Leaf Market · Burpee (each supplier's chrysanthemum seeds)
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing chrysanthemum (garden mum)" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 5b calendar · Plan your beds in the Garden Designer →
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Growing Chrysanthemum (Garden Mum) in USDA zone 5b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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