Height:

3.0-5.0 Feet

Spread:

1.5-2.0 Feet

Hardiness Zones:

3,4,5,6,7

Flower Color:

Blue shades

Foliage Color:

Green shades

Sunlight:

Full Sun (> 6 hrs. Direct Sun) Part Shade (4-6 hrs. Direct Sun)

Water Requirements:

Average Water Needs

Soil Quality:

Average Soil Quality Fertile Soil Quality

Soil Chemistry:

Neutral Soil (pH = 7.0) Alkaline Soil (pH > 7.0)

Bloomtime:

Early Summer Late Summer Early Fall

Attracts Wings:

Attracts Butterflies Attracts Hummingbirds Bee Friendly

Critter Resistant:

Deer Resistant Rabbit Resistant

Seasonal Interest:

Dried Seed Heads

Growth Rate:

Medium

Garden Style:

Cottage Eclectic

Other Features:

Border Plant Cut Flower Cut Foliage Dried Flower Mass Planting Specimen Focal Point

Origin:

Not Native to North America

Delphiniums thrive in the cooler climates of the north country, though they will grow as far south as zone 7. The New Millenium hybrids, however, tend to be more tolerant of heat and humidity. They grow best in rich, well-drained soil with a basic pH. If your soil is naturally acidic, adding lime will help to provide these conditions. They are also heavy feeders. The addition of compost or manure to the soil as well the use of granular fertilizer will result in healthier, stronger plants.

Delphiniums can be grown in full sun or partial shade, though full sun may help to prevent powdery mildew. When planting, be sure to set the crown at or above soil level to avoid rot. Since their stems are hollow, taller varieties of Delphiniums should be staked to prevent damage from wind and rain. These new hybrids tend to be longer lived than their short-lived cousins but may be propagated from basal cuttings.

Growing Temperature:

65-75° F days
50-55° F nights

Holding Temperature:

50-55° F

Soil PH:

5.8-6.2

EC (What is EC?):

1.5-2.0 pour through method

Fertility:

A balanced fertilizer using calcium and potassium nitrate is preferred. Once flower initiation occurs, use less nitrogen and more potassium and phosphorus. Feed 75-100 ppm N at each watering.

For Controlled Release or Slow Release Fertilizer, see your preferred supplier for recommended rates for incorporation or top dressing, as it varies by fertilizer.

Vernalization:

Not required.

Pests & Diseases:

Aphids, borers, leaf miner, mites (cyclamen, brood, two-spotted spider), lily aphid, green peach aphid (Myzus) in greenhouse, beetles, cutworm, sowbugs, slugs, nematodes, aster leafhopper, thrips.

Impatiens necrotic spot virus, viruses, aster yellows, Verticillium wilt, bacterial blight (Pseudomonas), stem canker (Fusarium), damping off, smut, crown rots, Botrytis blight, black leg (Erwinia), crown gall, leaf spots, powdery mildew, rusts, chlorosis (low temperature, wet soil).

Watch for powdery mildew, botrytis and erwinia soft rot when high humidity and temperatures occur. Avoid stagnant air conditions, especially when flower buds are forming. A general fungicide treatment is advisable if these environmental conditions persist.

Potting & Timing:

Plant in early to late spring.

Moisture:

Water well when first planted, then keep damp to moist, but not soggy, until initial bud breaks. Do not let the soil dry out completely. Avoid overhead watering to prevent diseases. Avoid overwatering and wet foliage after flower bud initiation occurs.

Planting Level:

Place crown at or just below soil surface.

PGRs/Pinching:

Apply Bonzi at 30 ppm or Sumagic at 5 ppm as a spray when flower stems begin to grow beyond the foliage.

Lighting:

For best results grow under photoperiods of 12 hours or longer.

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