Growing chrysanthemums in USDA Zone 8 means gardening with mild winters and a long growing season, with a last frost in early spring and a first frost in late autumn. The average last spring frost falls around Mar 1–15 and the average first autumn frost around Nov 15–Dec 1, with average winter lows of 10 to 20°F. Those are USDA/NOAA zone averages, not promises for any one garden — check your local extension service. Chrysanthemums are a reliable choice in this zone, and this guide covers when to plant chrysanthemums in Zone 8, with the soil, spacing, sun, water and care it needs. Use the Zone 8 planting calendar to see what else to sow alongside it.
Zone 8 at a glance
USDA Zone 8 has average winter lows of 10 to 20°F, a last frost around Mar 1–15 and a first frost around Nov 15–Dec 1. Plan around those averages, not the calendar: a cold spring or a warm autumn can shift everything by a week or two, so check your local extension service for your area. Chrysanthemums are hardy to cold, so time planting around the frost dates first and everything else second.
| Detail | Zone 8 guidance |
|---|---|
| Average last spring frost | Mar 1–15 (average/range) |
| Average first autumn frost | Nov 15–Dec 1 (average/range) |
| Days to germination | 7–14 days |
| Days to maturity | 90–120 days |
| Sowing | Start indoors, or plant young plants in spring (March to April) |
| Transplanting | March to April, after the average last frost (Mar 1–15) |
| Harvest | Flowers in autumn, 90–120 days after planting |
| Sun | full sun |
| Soil pH | 6.0–7.0 |
| Spacing | 12–18 inches |
| Water needs | moderate |
When to plant chrysanthemums in Zone 8
February to March, about 6–8 weeks before the average last frost. Seeds germinate in 7–14 days, and the crop takes 90–120 days to maturity, so work the dates back from the frost averages: flowers in autumn, 90–120 days after planting. If you are unsure of your own dates, the seed-starting calculator will work the timing out from your last frost. Frost dates are zone averages — check your local extension service before you commit to a date.
Starting chrysanthemums in Zone 8
Start chrysanthemums indoors in February to March, or buy young plants in spring (March to April) — most gardeners grow named varieties from cuttings or young plants rather than seed. Set plants out after the last frost, spacing them 12–18 inches apart, and pinch the growing tips through early summer to make bushy plants with many flowers.
Soil, spacing, sun and water
Chrysanthemums want full sun and fertile, well-drained soil with a pH of 6.0–7.0. Dig in compost before planting and mulch to hold moisture through summer. They are short-day plants, which means they flower as the days shorten in autumn — this is why pinching stops in midsummer, so buds can form. Space plants 12–18 inches apart — it is tempting to crowd plants in, but crowded plants stay small and invite disease, so measure the bed out before you plant. Chrysanthemums need moderate water: water deeply and less often rather than lightly every day, water at the base in the morning so leaves dry before night, and mulch to keep the soil evenly moist. Check the soil a finger's depth down and water when it feels dry there.
Companion planting
Good companions for chrysanthemums include lavender, marigolds, garlic, chives. The companion planting finder can suggest combinations for your whole bed. Related reading: Asters. Avoid planting chrysanthemums where the same family (Asteraceae) grew last year.
Pests and problems
The common pests and problems to watch for with chrysanthemums are aphids, slugs, thrips. Inspect plants regularly, especially the undersides of leaves, and act early: hand-pick larger pests, wash aphids off with a strong jet of water, and remove badly affected leaves rather than waiting for the problem to spread. Aphids gather on buds in autumn — wash them off with water. Slugs can damage young plants in spring, and thrips can distort flowers. Good air flow from proper spacing and watering at the base keeps most problems at bay.
Harvest and storage
Chrysanthemums flower in autumn, 90–120 days after planting, and are the classic autumn cut flower. Cut stems when flowers are mostly open, in the morning, and put them straight into cool water. After flowering, cut plants back and mulch the crowns — in Zone 8, garden chrysanthemums often overwinter and return the following year.
Making the most of Zone 8
Zone 8 chrysanthemums are the autumn showpiece: plant in spring, pinch through early summer, then stop and let the shortening days do their work. The reward is a burst of colour in October and November, when the rest of the garden is winding down. Keep a simple notebook of what you sowed, when it went out, and when it flowered or fruited — after one season you will have a record far more useful to your own garden than any general guide.
Related Zone 8 guides in this series: March in Zone 8 and Chrysanthemums in Zone 1.
Frequently asked questions
When should I plant chrysanthemums in Zone 8?
Work back from the average last frost around Mar 1–15: start indoors, or plant young plants in spring (march to april). Check your local extension service — these are zone averages, not exact dates for your garden.
How long do chrysanthemums take to grow in Zone 8?
Seeds germinate in 7–14 days, and the crop takes 90–120 days to maturity. In Zone 8, cool soil can slow growth early in the season, so allow the longer end of the range.
When should I stop pinching chrysanthemums?
Stop pinching by midsummer so flower buds can form — chrysanthemums flower as days shorten in autumn, and late pinching removes the buds. Pinch young plants through late spring and early summer only.
What soil and spacing do chrysanthemums need in Zone 8?
Chrysanthemums need full sun and soil pH 6.0–7.0, spaced 12–18 inches apart. Dig in well-rotted compost, water deeply, mulch, and test your soil through your local extension service.