Flowering Kale: Complete Guide to Growing Ornamental Kale from Seed
Flowering kale is one of the most underrated plants in the garden world. While everyone else is scrambling to keep summer annuals alive through fall heat, flowering kale is just getting started — its colors intensifying with every cool night, putting on a show that lasts from September all the way through winter. If you want bold, long-lasting fall and winter color that actually thrives in cold weather, flowering kale is your answer.
This complete guide covers everything you need to know about growing flowering kale from seed — varieties, timing, seed starting, transplanting, care, and troubleshooting.
Also see: How to Grow Flowering Kale from Seed: Step-by-Step Guide from Sowing to Gallon Pots
What Is Flowering Kale?
Flowering kale (also called ornamental kale) is a cool-season plant grown for its spectacular foliage rather than its flowers. It's a cultivated form of Brassica oleracea — the same species as edible kale, cabbage, and broccoli — but bred specifically for dramatic leaf color and form. The "flowers" are actually tightly packed rosettes of leaves in shades of white, pink, rose, red, and purple, often with contrasting green outer leaves.
Key facts about flowering kale:
- Cool-season plant that thrives in temperatures of 45–65°F
- Colors intensify after frost — cold actually makes it more beautiful
- Lasts through hard freezes (down to 5–10°F in many varieties)
- Grows 12–18" tall and wide depending on variety
- Edible, though bitter — primarily grown as an ornamental
- Perfect for fall containers, borders, and winter garden displays
Best Flowering Kale Varieties to Grow from Seed
Crane Series — The Premier Flowering Kale for Gardens & Containers
The Crane series is widely considered the gold standard of flowering kale. Large, well-formed rosettes with excellent color intensity and cold tolerance. Available in a beautiful range of colors.
Flowering Kale Crane Pink — Soft pink centers with contrasting dark green outer leaves. One of the most popular flowering kale varieties for fall containers and borders. Colors deepen beautifully after frost.
Flowering Kale Crane Rose — Deep rose-pink centers with bold green outer leaves. A richer, more saturated color than Crane Pink — stunning in mass plantings and large containers. Excellent frost tolerance.
Flowering Kale Crane Red — Bold, deep red centers that intensify dramatically after frost. One of the most striking flowering kale varieties available — a showstopper in fall and winter displays.
Flowering Kale Crane White — Crisp white centers with dark green outer leaves. Clean, elegant, and versatile — pairs beautifully with any color scheme. A classic choice for formal fall displays and holiday containers.
Flowering Kale Crane Bicolor — A stunning mix of pink and white within the same rosette. Each plant is unique — no two look exactly alike. Excellent for mixed container plantings and fall borders.
Also see: Ornamental Kale: Cold-Season Beauty and Profitable Retail Favorite
Flare Series — Feathery, Fringed Leaves for a Different Look
The Flare series has deeply fringed, feathery leaves that give a softer, more textural look than the smooth-leaved Crane series. Beautiful in mixed arrangements and containers.
Flowering Kale Rose Flare — Deeply fringed rose-pink leaves with a soft, feathery texture. A beautiful contrast to smooth-leaved varieties in mixed plantings. Excellent cold tolerance and long display season.
Flowering Kale White Flare — Fringed white leaves with a delicate, lacy appearance. Stunning in holiday containers and winter window boxes. Pairs beautifully with red and rose varieties for a festive display.
Nagoya Series — Compact & Uniform for Mass Plantings
The Nagoya series is known for its compact, uniform habit — ideal for mass plantings, retail displays, and formal garden borders where consistency matters.
Nagoya Rose — Compact, uniform rosettes in soft rose-pink. Excellent uniformity makes it ideal for mass plantings and retail production. One of the most popular Nagoya varieties.
Nagoya Red — Deep red centers on compact, uniform plants. Excellent for mass plantings and fall retail displays. Colors intensify dramatically after frost for a spectacular late-season show.
Also see: Late Summer Gardening: What to Plant Now for a Fall Harvest
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Need bulk quantities? Visit our sister site: Trailing Petunia Bulk Seeds for larger pack options.
When to Start Flowering Kale Seeds
Timing is everything with flowering kale. The goal is to have transplant-ready plants when temperatures begin to cool in late summer and fall. Here's the general schedule:
| Zone | Start Seeds Indoors | Transplant Outdoors | Peak Display |
|---|---|---|---|
| Zones 3–4 | Late June – Early July | Late July – August | September – October |
| Zones 5–6 | Early – Mid July | Mid – Late August | October – November |
| Zones 7–8 | Mid July – Early August | September | October – December |
| Zones 9–10 | August – September | October – November | November – February |
Note: Flowering kale takes approximately 10–12 weeks from seed to display-ready size. Work backward from your desired display date to determine your seed start date.
How to Start Flowering Kale Seeds Indoors
- Fill trays with moist seed-starting mix. Use a fine, well-draining mix. Flowering kale seeds are small — good seed-to-medium contact is important.
- Sow seeds on the surface and cover lightly with 1/8" of mix. Unlike some flowers, kale seeds do not need light to germinate — a light covering helps.
- Maintain 65–70°F soil temperature. Flowering kale prefers cooler germination temperatures than most summer annuals. Avoid using a heat mat — room temperature is usually ideal.
- Expect germination in 4–7 days. Brassica seeds germinate quickly and reliably.
- Move to bright light immediately after germination. Provide 14–16 hours of light under grow lights to prevent leggy seedlings.
- Thin to one seedling per cell once the first true leaves appear.
- Transplant to 4" pots when seedlings have 3–4 true leaves, then to final containers or garden beds when plants are 4–6" tall.
Also see: Cool-Season Cut Flowers from Seed: Plant Now, Harvest Early
Growing Flowering Kale Outdoors: Care Guide
Sunlight
Flowering kale performs best in full sun — 6+ hours of direct sunlight daily. In partial shade, plants will grow but color development will be less intense. The most vibrant color always comes from plants grown in full sun with cool temperatures.
Soil & Planting
Plant in well-draining soil with a pH of 6.0–7.0. Space plants 12–18" apart for good air circulation — crowding increases the risk of fungal disease. In containers, use one plant per 10–12" pot or 2–3 plants in a larger 16–18" container.
Watering
Water consistently but avoid overwatering. Allow the top inch of soil to dry between waterings. Water at the base of the plant — wet foliage can encourage fungal issues. In containers, check daily as they dry out faster than garden beds.
Fertilizing
Apply a balanced slow-release fertilizer at planting. Avoid high-nitrogen fertilizers once plants are established — too much nitrogen promotes leafy green growth at the expense of the colorful center rosette. A light application of balanced liquid fertilizer every 3–4 weeks is sufficient.
Cold Tolerance
This is where flowering kale truly shines. Light frost (28–32°F) actually intensifies the colors — especially pinks, reds, and purples. Most varieties tolerate temperatures down to 5–10°F, making them one of the most cold-hardy ornamental plants available. In Zones 7–10, flowering kale can provide color all the way through winter.
Flowering Kale in Containers
Flowering kale is one of the best plants for fall and winter containers. Its bold rosettes provide structure and color when most other plants have faded. Here are some design tips:
- Thriller-filler-spiller formula: Use flowering kale as the "thriller" (tall, bold centerpiece) in mixed fall containers. Pair with trailing pansies or violas as spillers and compact mums or asters as fillers.
- Mix series for texture: Combine smooth-leaved Crane varieties with fringed Flare varieties for a rich textural contrast.
- Color coordinate: White Crane + Rose Flare + Nagoya Red creates a stunning red-white-pink holiday container.
- Use deep containers: Flowering kale develops a substantial root system. Use containers at least 10–12" deep for best results.
Frequently Asked Questions: Flowering Kale
What is flowering kale?
Flowering kale (ornamental kale) is a cool-season plant grown for its spectacular rosettes of colorful leaves in shades of white, pink, rose, red, and purple. It's a cultivated form of Brassica oleracea — the same species as edible kale — but bred specifically for ornamental display rather than eating.
Is flowering kale edible?
Yes, flowering kale is technically edible, but it's quite bitter and tough compared to edible kale varieties. It's primarily grown as an ornamental plant. The leaves are safe to eat but most gardeners grow it purely for its visual impact.
How long does flowering kale last?
Flowering kale is remarkably long-lasting — it can provide color for 3–5 months in the garden, from early fall through winter. In Zones 7–10, it often lasts all the way through February or March. Cold temperatures actually improve its appearance, with colors intensifying after frost.
Does flowering kale come back every year?
Flowering kale is a biennial — it completes its life cycle over two years. In its first year it produces the colorful rosette; in its second year it bolts and flowers. Most gardeners treat it as an annual, starting fresh seeds each season for the best ornamental display.
What is the difference between flowering kale and ornamental cabbage?
Both are Brassica oleracea cultivars grown for ornamental foliage. Flowering kale typically has more open, frilly, or feathered leaves, while ornamental cabbage has tighter, more rounded heads that resemble a cabbage. Both are equally cold-hardy and provide similar fall and winter color.
When should I plant flowering kale?
Start seeds indoors 10–12 weeks before you want plants on display. For fall color, that means starting seeds in July or August depending on your zone. Transplant outdoors when temperatures begin to cool — flowering kale performs best when daytime highs are below 75°F.
Why is my flowering kale not turning color?
Flowering kale needs cool temperatures to develop its best color — ideally below 60°F at night. If your plants are still green, they likely haven't experienced enough cold yet. Be patient — once temperatures drop, the color change happens quickly. Also ensure plants are in full sun, as shade reduces color intensity.
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