Heirloom

Benary's Giant Deep Red

Zinnia elegans

Photo: Daffgatter · Wikimedia Commons · (CC0)

Benary's Giant Deep Red is a spectacular heirloom celosia (cockscomb) featuring velvety, deep crimson flower heads that can reach 6-8 inches across. The densely ruffled plumes emerge on sturdy, branching plants reaching 24-30 inches tall. Blooming within 75-90 days, it's prized for its rich color intensity and dramatic garden impact. An excellent cut flower and landscape focal point for full-sun borders.

Harvest

75-90d

Days to harvest

📅

Sun

Full sun

☀️

Zones

2–11

USDA hardiness

🗺️

Height

0-3 feet

📏

Planting Timeline

Zone:

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Start Indoors

Transplant

Direct Sow

Start Indoors

Transplant

Direct Sow

Showing dates for Benary's Giant Deep Red in USDA Zone 7

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Zone Map

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Benary's Giant Deep Red · Zones 2–11

What grows well in Zone 7? →

Growing Details

Difficulty

Easy

Spacing18-24 inches

SoilWell-drained loam, fertile

WaterRegular, consistent moisture

SeasonWarm season annual

ColorDeep red

Size4-6"

Zone-by-Zone Planting Calendar

Zone	Indoor Start	Transplant	Direct Sow	Harvest
Zone 1	May – June	July – August	July – September	—
Zone 2	April – May	June – July	June – August	—
Zone 11	January – January	January – February	January – March	—
Zone 12	January – January	January – February	January – March	—
Zone 13	January – January	January – February	January – March	—
Zone 3	April – May	June – July	June – August	—
Zone 4	March – April	June – June	June – July	—
Zone 5	March – April	May – June	May – July	—
Zone 6	March – April	May – June	May – July	—
Zone 7	February – March	April – May	April – June	—
Zone 8	February – March	April – May	April – June	—
Zone 9	January – February	March – April	March – May	—
Zone 10	January – January	February – March	February – April	—

Succession Planting

Direct sow every 2–3 weeks from your last frost date through early summer — in zone 7, that means roughly April 1 through June 15. Benary's Giant takes 75–90 days to first bloom, so a mid-June sowing will carry you into September with fresh flowers. Once daytime highs are consistently above 90°F, germination gets unreliable and early growth stalls, so don't push sowings too late in the season.

If you're growing for cut flowers, staggered sowings matter more than if you just want a full bed. A 3-week gap between plantings keeps a steady rotation of stems coming rather than one big flush. Indoors, start seeds 4–6 weeks before your transplant date; zinnias don't love being root-bound, so don't start them too early.

Complete Growing Guide

Recommended by the Association of Specialty Cut Flower Growers. High yields of long, sturdy stems with 4-6" fully double, dahlia-like blooms. Excellent vase life. Vigorous plants hold up well in summer heat and rain. Low susceptibility to powdery mildew. Cut-and-come-again flower, yielding multiple cuts over the season. According to Johnny's Selected Seeds, Benary's Giant Deep Red is 75 - 90 days to maturity, annual, open pollinated. Notable features: Use for Cut Flowers and Bouquets.

Light: Full sun (6 or more hours of direct sunlight a day). Soil: High Organic Matter, Loam (Silt). Soil pH: Acid (<6.0), Alkaline (>8.0), Neutral (6.0-8.0). Drainage: Good Drainage, Occasionally Dry. Height: 0 ft. 6 in. - 3 ft. 0 in.. Spread: 0 ft. 8 in. - 1 ft. 0 in.. Spacing: 12 inches-3 feet. Growth rate: Rapid. Maintenance: Medium. Propagation: Seed. Regions: Coastal, Mountains, Piedmont.

Harvesting

Benary's Giant Deep Red reaches harvest at 75 - 90 days from sowing per Johnny's Selected Seeds. Expect 4-6" at peak. As an annual, harvest continues until frost ends the season.

Type: Achene.

Storage & Preservation

For maximum vase life, cut stems in early morning when fully hydrated. Remove lower foliage, recut stems at a 45° angle, and immediately place in room-temperature water with floral preservative. Change water every 2-3 days. Store in a cool location (65-72°F) away from direct sunlight, ethylene-producing fruits, and drafts. Blooms last 7-10 days indoors. For preservation, try air-drying upside-down in a dark, well-ventilated space (2-3 weeks), pressing individual petals between paper, or silica gel drying for maintaining shape and color intensity.

History & Origin

Benary's Giant Deep Red is open-pollinated, meaning seed saved from healthy plants will produce true-to-type offspring. Listed in the Johnny's Selected Seeds catalog.

Origin: Mexico

Advantages

+Produces long, sturdy stems ideal for professional cut flower arrangements
+Large 4-6" fully double dahlia-like blooms with deep red color
+Excellent vase life extends the value of each cut flower
+Cut-and-come-again variety yields multiple harvests throughout the season
+Vigorous plants withstand summer heat, rain, and resist powdery mildew

Considerations

-Requires 75-90 days to first bloom, extending time to harvest
-Deep red color may fade in intense direct sunlight over time
-Needs consistent deadheading to maintain continuous production
-Large blooms demand sturdy support stakes in windy conditions

Companion Plants

Marigolds (especially Tagetes patula) and sweet alyssum are the most practical companions here. Tagetes patula releases thiophenes from its roots that suppress soil nematodes, and the flower scent confuses aphids and whiteflies above ground. Sweet alyssum draws hoverflies, whose larvae eat aphids — plant it at the edges of your zinnia bed and it does quiet, useful work all season. Cosmos and celosia make sense alongside Benary's Giant for a different reason: they share the same light and water requirements, so you're not juggling competing needs, and mixing heights keeps air moving through the planting.

Black walnut is the one to give a wide berth. Juglone — the compound black walnut roots and decomposing hulls release — builds up in the soil over years, and zinnias are sensitive enough that even a planting 40 feet from an established tree can show suppressed growth and poor germination. Fennel causes a similar problem through allelopathic root compounds, though for a different reason: it actively inhibits the germination and development of many annuals growing nearby and is better sited in its own isolated patch.

Plant Together

Marigolds

Repel nematodes and aphids while attracting beneficial insects

Basil

Deters thrips and aphids that commonly attack zinnias

Nasturtiums

Act as trap crop for aphids and cucumber beetles

Cosmos

Attract beneficial predatory insects and pollinators

Sunflowers

Provide support structure and attract beneficial birds

Cleome

Attract hoverflies and other beneficial insects that control pests

Celosia

Similar growing requirements and attract complementary pollinators

Sweet Alyssum

Ground cover that attracts beneficial wasps and hover flies

Keep Apart

Black Walnut

Produces juglone which is toxic to zinnias and causes wilting

Fennel

Allelopathic properties inhibit zinnia growth and development

Eucalyptus

Root secretions and leaf litter suppress zinnia germination and growth

Pests & Disease Resistance

Diseases

Powdery mildew (low susceptibility)

Troubleshooting Benary's Giant Deep Red

What you'll see, why it happens, and what to do about it.

White powdery coating on upper leaf surfaces, usually appearing mid-summer when nights cool down

Likely Causes

Powdery mildew (Erysiphe cichoracearum) — fungal spores spread by wind, thrives in warm days and cool humid nights
Crowded planting that restricts airflow between plants

What to Do

1.Space plants at least 18 inches apart from the start — cramming them in is the fastest way to invite this
2.Remove and bag heavily infected leaves; don't compost them
3.Spray with a diluted neem oil solution (2 tbsp per gallon) every 7 days as a preventive once you see the first signs

Seedlings collapse at soil level, stems pinched and dark at the base, within the first 2 weeks after germination

Likely Causes

Damping off — typically Pythium or Rhizoctonia fungi, triggered by overwatering and poor drainage in seed trays
Using old, non-sterile potting mix that holds too much moisture

What to Do

1.Start fresh with sterile seed-starting mix and clean trays — reusing last year's mix without sterilizing it is asking for trouble
2.Water from the bottom, and let the surface dry slightly between waterings
3.Run a small fan nearby to keep air moving across the trays

Buds form but flowers fail to open fully, or petals brown at the edges before the bloom expands

Likely Causes

Botrytis cinerea (gray mold) — common in wet or humid stretches, especially if spent blooms aren't removed
Extended cool, overcast weather slowing down a warm-season annual that wants 70–85°F days to perform

What to Do

1.Deadhead consistently — spent blooms sitting on the plant are where Botrytis gets its foothold
2.Cut flowers early in the morning when stems are turgid, and get them out of the bed
3.If you see gray fuzzy spore masses on any tissue, remove that material immediately and dispose of it away from the garden

Plants look stunted at 3–4 weeks, leaves pale green overall rather than a specific pattern, not growing toward the 2–3 foot mature height

Likely Causes

Nitrogen deficiency in sandy or low-organic-matter soil
Root-bound transplants that were left in cell trays too long before going in the ground

What to Do

1.Side-dress with a balanced granular fertilizer (something like 10-10-10) at about 4 weeks after transplant, following label rates
2.Check your transplants before planting — if roots are circling the bottom of the plug, loosen them gently before setting in the hole
3.Incorporate compost into beds before the season; zinnias aren't heavy feeders, but they won't thrive in depleted soil

Frequently Asked Questions

How long do Benary's Giant Deep Red flowers last in a vase?▼

With proper care, these dahlia-like blooms typically last 7-10 days in a vase. To maximize longevity, use floral preservative, change water every 2-3 days, remove lower foliage, and keep stems trimmed at a 45° angle. Keep the arrangement in a cool location away from direct sunlight and ripening fruit, which produce ethylene gas that shortens vase life.

Is Benary's Giant Deep Red good for beginner flower growers?▼

Yes, this variety is excellent for beginners. It's classified as easy to grow and vigorous, holding up well in summer heat and rain. Plants produce multiple cuts over the season (cut-and-come-again habit), making it rewarding for new growers. The variety has low susceptibility to powdery mildew, reducing disease management concerns.

Can you grow Benary's Giant Deep Red in containers?▼

Yes, containers are suitable for this variety. Ensure pots are at least 12-18 inches deep with excellent drainage. Use quality potting soil and provide consistent moisture during growing season. Container plants may need staking due to 4-6" blooms on tall stems. Place containers in full sun (6+ hours daily) and deadhead regularly to encourage continuous blooming throughout the season.

What makes Benary's Giant Deep Red ideal for cut flowers?▼

This award-winning variety (recommended by the Association of Specialty Cut Flower Growers) produces long, sturdy stems perfect for arrangements. The fully double, dahlia-like blooms reach 4-6" in diameter and offer excellent vase life. High yields and cut-and-come-again flowering provide multiple harvests per season, making it economical for commercial and home cut-flower production.

When should I plant Benary's Giant Deep Red?▼

Start seeds indoors 6-8 weeks before your last frost date, or direct sow after all danger of frost has passed. These warm-season annuals need soil and air temperatures of at least 60°F for germination. In most zones, outdoor planting occurs late April through May. For continuous blooms, succession plant every 2-3 weeks for extended harvest throughout the growing season.

How often should I harvest Benary's Giant Deep Red blooms?▼

Harvest regularly, ideally every 2-3 days, to encourage continuous flowering. Cut stems early in the morning when fully hydrated, removing at least 2-3 sets of leaves to promote branching and future blooms. This cut-and-come-again variety can produce multiple harvests over 75-90 days to first bloom, then continue flowering until frost in fall.