Louisiana iris (Iris 'Professor Neil')
Stunning wine red Louisiana iris, Iris 'Professor Neil' thrives in wet soils. A low-maintenance perennial for water and rain gardens.
Complete Plant Information
Overview
Iris ‘Professor Neil’ offers gardeners a spectacular display of color, belonging to the highly resilient group known as Louisiana iris. These beardless hybrids are celebrated for their ability to thrive where other perennials struggle—namely, wet or soggy conditions. The deep wine red blooms of Iris ‘Professor Neil’ are a significant draw, providing rich contrast in waterside plantings between May and June.
As an herbaceous perennial, this variety establishes a strong root system, making it very low maintenance once sited correctly. Gardeners seeking reliable performance in rain gardens, beside ponds, or in naturally damp low spots will find this Louisiana iris exceptionally rewarding. It readily adapts to various soil types, provided moisture is consistently available throughout the growing season.
The structure of the Louisiana iris group, descended from species native to Southern bayous, ensures that Iris ‘Professor Neil’ is robust and vigorous while growing. Expect attractive, upright foliage complementing the vibrant flowers, fitting perfectly into naturalized scenes or formal water garden designs.
Fast Facts
- Plant Family: Iridaceae
- Plant Type: Herbaceous perennial
- Hardiness Zones: USDA Zones 5-9
- Size at Maturity:
- Height: 2-3 ft
- Spread: 1-2 ft
- Bloom Time: May to June
- Bloom Description: Wine red
- Sun Exposure: Full sun to part shade
- Water Needs: Medium to wet
- Maintenance Level: Low
How to Grow
The key distinction for successfully growing Iris ‘Professor Neil’ is managing moisture. These irises prefer average to rich, slightly acidic soils that remain consistently moist or even wet. While they tolerate clay soils well, avoid sharply draining sandy sites unless heavily amended with organic matter. For the best flowering, aim for full sun, though some afternoon shade is beneficial in hotter climates.
Planting should ideally occur in late spring (early May to early June) or, alternatively, in early fall (mid-August to mid-September) in milder climates. Before planting, soak the rhizome overnight. Position the rhizome so the top is barely covered, approximately 1 inch below the soil surface. This water-loving iris flourishes when kept saturated; it can even handle up to 6 inches of standing water.
Ongoing care for your Louisiana iris is simple due to its low maintenance requirements. Deep watering is crucial during dry spells, as the soil should never fully dry out during the growing season. Protect the rhizomes year-round with a layer of pine needles, adding extra straw mulch in winter, especially where hard freezes occur, to insulate against cold stress and sunscald. Propagation is achieved easily through division.
Landscape Uses
Louisiana irises are indispensable for creating moist habitat features in the landscape. Iris ‘Professor Neil’ excels when positioned at pond or stream margins, in bog gardens, or integrated into designed rain gardens where water naturally collects. If you have a fishpond, sinking pots containing this variety directly into the water is an excellent way to feature its blooms prominently.
Due to their moisture demands, these plants serve as excellent living borders for water features, softening hard edges and integrating built structures with the natural environment. They also naturalize effectively in suitable wet meadows or low-lying areas of the yard lacking adequate drainage for drier species.
Consider pairing the upright foliage of Iris ‘Professor Neil’ with moisture-loving texture plants like Japanese iris (in slightly less saturated soils), sedges, or cardinal flower for a dynamic, water-centric display throughout the warm season.
Standout Features
Flower Qualities
- Showy
Noteworthy Characteristics
Louisiana iris is a catchall term used to describe a large group of rhizomatous beardless interspecific hybrid irises that contain varying percentages of the five species which make up the Louisiana Iris Group: Iris fulva, Iris hexagona, Iris brevicaulis, Iris giganticaerulea and Iris nelsonii. These irises will spontaneously hybridize in the wild. Species in the Louisiana iris group are native to the bayous and marshes, damp hillsides, swamps, and riversides of Southern Louisiana to Florida and the Carolinas. Hybrid cultivars like Iris ‘Professor Neil’ are typically winter hardy to USDA Zone 5, offering deep red flowers with a bright yellow signal and a musky fragrance.
Tolerances
- Deer
- Clay Soil
- Wet Soil
Potential Problems
Though generally low maintenance, Louisiana iris varieties, including Iris ‘Professor Neil’, can be susceptible to certain fungal and pest issues common to the genus. Watch the foliage for Leaf spot, and be vigilant about signs of bacterial soft rot or root rot, which indicate overly cool or poorly draining conditions, even for a water-loving plant. Pest control focuses on common garden nuisances like slugs, snails, and aphids; however, iris borers can cause significant damage in regions where they are prevalent. Promptly removing infected or damaged foliage helps manage disease spread, and deer tend to avoid this robust plant.
Frequently Asked Questions
What hardiness zones is Louisiana iris suitable for?
Iris ‘Professor Neil’ is reliably hardy in USDA Zones 5 through 9, allowing cultivation across a wide range of temperate climates, provided moisture needs are met.
How large does Iris ‘Professor Neil’ grow?
This cultivar typically reaches a mature height between 2 and 3 feet tall, with a spread of 1 to 2 feet, creating an upright presence in the garden.
What sun exposure does Iris ‘Professor Neil’ need?
For the most vibrant blooming, this Louisiana iris requires Full sun to part shade conditions. Ensure it receives ample light, especially in cooler regions.
When does Louisiana iris bloom?
You can anticipate the wine red blooms of Iris ‘Professor Neil’ to appear reliably from May to June.
Conclusion
For gardeners in need of reliable, colorful saturation near water features, Iris ‘Professor Neil’ stands out as an exceptional choice. Its tolerance for wet soils and clay makes this Louisiana iris a versatile workhorse with dramatic, showy blooms. Be sure to check USDA Zone compatibility and plan your planting for late spring for the best establishment.
Companion Planting
Because Iris ‘Professor Neil’ requires constant moisture, companion plants must share similar wetland or boggy requirements. Excellent partners include Marsh Marigold (Caltha palustris), which offers early spring color, and various rushes and sedges (Carex species) for upright, structural contrast. For height variation near pond edges, consider planting upright moisture-loving perennials like Marsh Milkweed (Asclepias incarnata) or Swamp Sunflower (Heliopsis helianthoides) to complement the mid-sized growth habit of the Louisiana iris.
Propagation Tips
The primary and easiest method for increasing your stock of Iris ‘Professor Neil’ is through vegetative division. Since it is a rhizomatous perennial, plants benefit from being divided every few years to maintain vigor and prevent overcrowding, usually done right after flowering ends, in late spring or early summer. Ensure each division retains a healthy section of rhizome, a fan of leaves, and a growing eye (bud). If you wait until fall planting season, ensure the divided sections have sufficient time to establish roots before the winter freeze, particularly in the colder reaches of zones 5 and 6.
