Iris virginica, commonly known in the gardening world as the Southern blue flag iris or Virginia iris, is a mesmerizing flower-loving appreciated by gardeners worldwide. If you love colourful and stunning flowering plants that also require little to no effort on your part to thrive, the Southern blue flag iris is a perfect choice!
As mentioned above, the Southern blue flag iris is a popular ornamental worldwide, prized for its hypnotic blooms that can bring any dull garden back to life and fill it with beneficial pollinators during the warm season.
This plant is usually a focal point perfect for a wide range of landscapes, and it can be cultivated both in indoor and outdoor settings. It is very important to mention that the blue iris is an aquatic plant, but it will also do nicely and look absolutely marvellous as a cut flower in your favourite vase.
A secret tip to keep in mind – the perfect flowers to harvest are always those not-fully-bloomed.
Besides its charming appearance, the Southern blue flag iris brings extra points to the table with its friendly, easy-to-please nature. This flowering plant will remain healthy and happy in a wide variety of environmental and growing conditions.
From lighting exposure of full sunlight through afternoon shade to its tolerance of over-watering, the Southern blue flag iris will appreciate any type of environment and it will also forgive you if you are too busy to spoil it with attention. In other words, this is a one-of-a-kind plant that makes a perfect addition to any garden!
To make things easier, we’ve created this complete guide to growing and caring for Iris virginica a.k.a. the Southern blue flag iris. Keep reading to find out everything that is out there to know about this fascinating plant! By the end of this article, we are certain that this flower would have become your next favourite ornamental companion.
About Southern Blue Flag Iris
- The Southern blue flag iris belongs to the Iridaceae family. It shares this family with other 65 interesting, well-known genera including Crocus, Dierama, Dietes, Freesia, Gladiolus, Herbertia, Nemastylis, Thereianthus, Tigridia, and Tritonia.
- Iris virginica originates from the Southeastern United States. In its native habitat, in general, this species occurs along the coastal plains of Texas through Virginia.
- All parts of this plant may be pretty toxic to both humans and animals if ingested. Because of this, you should plant your Southern blue flag irises in an area that is out of reach for curious kids or pets. Likewise, make sure you wear gloves when handling your Iris virginica.
- Despite safety concerns, the Southern blue flag iris is an important medicinal plant for the Cherokee, one of the indigenous peoples of the United States in Southeastern Woodlands. They have been using this plant as a traditional remedy for centuries.
- The Southern blue flag iris works as a great treatment against various problems. Folks use its roots to make a paste and use it as a salve for the skin. A decoction of its root is used as a treatment for some urinary issues. Moreover, folks use the root to prepare an infusion that is effective against ailments of the liver.
- Some say that the Southern blue flag iris may be one of those Iris species that the Seminole people used as a treatment for the shock induced by an alligator bite.
- The Southern blue flag iris is generally considered a pond plant and it makes a wonderful addition to many landscape decorations, mostly for those that are more on the wet side. These include lily pools, rain gardens, bog gardens, ponds, streams, moist borders, wetlands, and containers.
- You can bring your garden to the next ornamental level by planting the Southern blue flag iris near other suitable companions. The most eye-appealing companion plants are Asters, Marsh Marigolds, Coneflowers, Button Bush, Primulas, Carex Aurea, Perfumed Spider Lily, and Scarlet Rose Mallow.
Southern Blue Flag Iris Features: An Overview
- The Southern blue flag iris is a perennial and semi-herbaceous flowering plant. Depending on the growing conditions, this plant can reach from 24 to 36 inches (60-90 cm) in both height and width.
- You will soon have numerous clumps of this plant in your garden as Iris virginica has a habit of spreading slowly via creeping rhizomes and forming superb colonies. The fleshy, rhizomatous roots spread underground and enjoy plenty of moisture.
- Its dense foliage consists of long, slender, sword-shaped, and bright green leaves that grow as wide as 0.4 to 1.2 inches (1-3 cm). In some cases, the leaves are much longer than the flower stalks. The stalks appear branched sometimes and have a slight zigzag overall look.
- The Southern blue flag iris usually blooms from late spring through early summer. During the warm months, tall stems will rise from the clumps and each show up with two or three beautiful, slightly fragrant blooms.
- Each Southern blue flag iris can have 2 to 6 blossoms once every year. The flowers measure about 3 inches (7 cm) in diameter and 1.6 inches (4 cm) in length.
- Their sepals and petals vary in colour from one specimen to another. They can exhibit shades of violet, light blue, or pinkish-white. The sepals feature a splash of yellow or orange-yellowish tint to white at their crest and present many veins.
- After its blooming period, the Southern blue flag iris may bear fruits. They are fat, green pods that grow as long as 2 inches (5 cm) and comprise several pale brown seeds that vary in shape.
Growing Southern Blue Flag Iris
Although the Southern blue flag iris is an aquatic plant, it does not behave like a spoiled and picky aquatic ornamental. If you already have a few different aquatic species of plants, you might be aware of how sensitive pond plants can be.
Luckily, this is not the case with the Southern blue flag iris! But even if the Southern blue flag iris is super easy-going in general, you will still need to meet some of its basic demands to see it thrive and enjoy its life. Let’s find out which are these!
After this plant’s watering needs, lighting exposure is probably the next most important factor in its caring routine. But do not get intimidated as the Southern blue flag iris is not fussy when it comes to its lighting preferences. It can grow nicely in a wide diversity of conditions from full sunlight to partial shade.
In most cases, the Southern blue flag iris does best when it receives as much bright, direct light as it can get. Yet, if you live in a spot with hot summers, we suggest you plant this flower where it will get partial shade during the afternoon.
The Southern blue flag iris might not be as cold-hardy as you would like, but this does not mean that you should avoid growing it in your garden if you live in a cool area. This plant is hardy only in the USDA regions 5 to 9. It does well in the range of temperatures under this hardiness zone, but it will actually appreciate more moderate climates.
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- Seeds germinate after 120 days of cold, moist stratification. Best planted outdoors in the fall.
- Iris virginica var. shrevei, Southern Blue Flag Iris, usually grows in large patches that expand outward from rhizomes. It is 2’-3’ high with the leaves on the flower stem growing slightly taller than the flower. Bloom time is from late spring to early summer. The bloom color is somewhat variable, but is most often a medium to pale blue violet.
- Below the yellow blotch, white and purple veined nectar guide lines fade to solid violet on the bottom edge. When the seed is close to maturity the weight of the pods will sometimes pull the stalk over to the ground where they will finish ripening and eventually split to drop the mature large brown seeds.
Last update on 2023-07-23 / Affiliate links / Images from Amazon Product Advertising API
You can protect your Southern blue flag iris from cold temperatures by bringing it inside in fall and allowing it to sit in water.
Since the Southern blue flag iris usually grows well in environments with plenty of moisture, some intruders like aphids, slugs, or snails will find it very attractive. As long as you keep the foliage of your plant clean and place traps around it, the slugs and snails will not bother it.
To avoid aphid infestations, make sure you use fertilizers that are low in nitrogen and also remove weeds regularly.
Planting Southern Blue Flag Iris
In areas where summers regularly bring high temperatures and/or high humidity levels, this plant’s roots will become prone to bacterial soft rot. If this happens, the foliage will turn yellow at its base and watery spots will appear on your plant’s rhizome. In serious cases, the infection may cause the entire rhizome to rot and emit a nasty smell.
You can prevent this unpleasant situation by planting your Southern blue flag iris on a substrate with excellent drainage. If you notice signs of an infection, you must dig the rhizome up from its growing medium, cut the rotten parts off, and then spray it with bactericides.
Likewise, the soil around your plant will require immediate disinfection or a replacement in case the infection is severe.
Besides the well-draining feature, the Southern blue flag iris also benefits from loose, fertile substrates that are rich in humus. Still, it will not show much dissatisfaction if you grow it on dry barren earth, so it is relatively easy to please in this chapter. The plant grows at its best in slightly acidic to neutral soils with a pH value of 6.0 to 7.0.
The best periods to fertilize your Southern blue flag iris would be early spring, early autumn, and once more right before its blooming period. Feed this plant with an organic, phosphorus-rich or balanced fertilizer. After you apply the fertilizer, you will have to water the plant to help its root absorb the nutrients.
Once its flowering period has come to an end, it would be wise to cut the bloom-bearing stalks off. This process will reduce nutrition consumption and may also help some varieties to produce flowers again. When autumn comes, you should prune the unhealthy or dead leaves to promote better air circulation.
There is no secret that you can grow the Southern blue flag iris in containers. For optimal results, choose a pot that you can fully place in water. In general, it is ok to do this if you dig it under the water at a maximum of 6 inches (15 cm) deep.
Watering Southern Blue Flag Iris
This type of Iris is a marginal aquatic plant, growing mostly around the edges of water rather than almost fully submerged in it.
Because of this, the Southern blue flag iris will tolerate standing in water constantly only if it is shallow and not deeper than 6 inches (15 cm) deep. It can also survive if you submerge it completely, but only for a short period.
The best thing about the Southern blue flag iris is that, unlike most other aquatic plants, it can withstand dry spells. However, the plant will still prefer to experience moisture consistently. If you want to help your plant retain more moisture, you can add a shallow layer of mulch around it.
In terms of watering frequency, this will depend on the environmental conditions the plant experiences. As a rule, it is best to spoil your Southern blue flag iris with water whenever you have the chance.
Over-watering is not a common issue regarding this flower, so you will in fact have to pay attention to its soil to prevent it from drying out entirely.
Propagating Southern Blue Flag Iris
Once you have a Southern blue flag iris, it will be only natural to secretly wish to enrich your collection with more of it. You can do this at home without spending any extra money on new specimens and trust us when we tell you that you will even have lots of fun while doing it.
With the Southern blue flag iris, the most common method of propagation is none other than dividing its roots. Before getting to work, make sure you equip your hands with gloves to avoid any contact with toxic substances from the plant’s roots.
When you are all set, you can dig the plant up in spring or after its flowering period, in autumn. Divide its rhizomes into three parts, then replant each section wherever you feel like it. Give the new plants a fresh start by watering them well right after planting.
Another great way to propagate your Southern blue flag iris is through seeds. This means that you will have to wait for your plant to bear fruits and collect the seeds before the fruits get the chance to ripe and self-seed.
After this step, you can sow the seeds directly into the moist ground without covering them with too much soil. Try to water the growing medium regularly to maintain the ideal levels of moisture. With good care, germination will occur in early spring.
There is no better way to diversify your plant collection than by adding an aquatic species to it, and the Southern blue flag iris is the right candidate for it. Needless to say that this gorgeous flowering plant is a much-needed statement ornamental piece for every respectable gardener. The blue iris is less invasive than other aquatic plants but just as easy-going and attractive.
Are you growing Southern blue flag iris? Share your experience in the comments section!