2020: Year of the Iris

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Every year, the National Garden Bureau, a non-profit organization promoting the pleasures of home gardening, selects one annual, one perennial, one edible plant, one shrub and one bulb to celebrate. It’s a great way to discover a new plant or to learn a bit more about a plant you may already be growing.

Let’s look at the perennial chosen for 2020, the iris.

Year of the Iris

Irises are among the easiest of perennials to grow from bulbs, roots or rhizomes. The genus includes some 250–300 species featuring showy flowers. In fact, the iris takes its name from the Greek word for a rainbow, which is also the name for the Greek goddess of the rainbow, Iris. A perfect name for flowers that bloom in a rainbow of colors!

Irises are native throughout the Northern Hemisphere, with most of the species being of Eurasian origin. 

Bearded iris ‘Concertina’ with 3 standards (upright) and 3 falls (curving downwards).

Each iris flower has two types of flower parts, the “standard” stands upright and includes 3 petals. The “falls” curve outwards and downwards and are made up of 3 sepals.

The three main types of garden iris are Bearded and Beardless, both with rhizomes, and Bulbous. Each has distinct features to complement your garden.

Plant Iris Depending on When You Want Them to Bloom…

  • Reticulate—Late winter/very early spring
  • Dwarf Bearded—Early to midspring
  • Tall Bearded—Mid to late spring
  • Siberian—Late spring to early summer
  • Dutch—Late spring to early summer
  • Japanese—Early summer
  • Louisiana—Early to midsummer
  • Reblooming Bearded—Midspring and again in late summer to early fall

Bearded Iris

On the bearded iris ‘Air of Mystery’, you can clearly see the bushy orange beard on the falls.

Bearded irises, including the common garden iris or German bearded iris (I. × germanica), are identified by thick, bushy “beards” on each of the falls (sepals) of the blossoms. These hair-like beards are fuzzy and stand up from the sepals.

The German bearded iris (I. × germanica) is a natural hybrid, derived from a long-ago cross between the pale purple-flowered Dalmatian iris (I. pallida) and the yellow-flowered Hungarian iris (I. variegata). It now comes in a huge range of colors and some 30,000 varieties. It’s hardy in USDA hardiness zones 3 to 10.

It has been crossed with other species, notably with the pygmy iris (I. pumila), giving rise to the great variety of modern dwarf and median bearded iris cultivars.

Bearded iris rhizomes. Photo: alabamaliving.co

Bearded irises are grown from a thick fleshy mostly underground stem called a “rhizome”. The rhizome feels like a tough potato in texture. These rhizomes should be planted in the ground during the fall months to give the roots time to become established before winter. When you buy a new iris by mail order, you’ll probably receive a rhizome with clipped roots and leaves. It can remain out of the ground for a week or two without serious harm, but the sooner it is planted, the better.

Plant your bearded iris in a sunny (6–8 hours) location with well-drained soil planted with the top of the rhizomes at the soil level or up to an inch (2.5 cm) below the surface of the ground. 

Bearded irises do best with an all-purpose fertilizer, applied once in early spring and once after blooming.

In about 2 or 3 years, a decrease in blooms usually indicates that it is time to divide your plants. Be sure to divide the plant by cutting the newer parts of the rhizome free from the old section and discard the older part.

Bearded irises are commonly divided into six groups depending on the size of the flower and the height of the plant.

  1. Miniature Dwarf Bearded
  2. Standard Dwarf
  3. Intermediate Bearded
  4. Border Bearded
  5. Miniature Tall Bearded
  6. Tall Bearded

Each one of these classifications have a different flowering time, height and habitat. 

Reblooming bearded iris ‘Peach Jam’.

Some bearded irises are “rebloomers”, blooming once more in the same growing season in the summer or fall. The number of blooms you will get later in the season varies by variety and local conditions. There are now reliable and attractive rebloomers available in the marketplace which will perform in most climates, but although they can’t be counted on in colder ones (USDA hardiness zones 3 to 5). You’ll probably see the term “reblooming iris” on the label.

Beardless Irises

The Siberian iris ‘Shakers Prayer’ has no beard.

Often used for naturalizing or perennial borders, beardless irises are an easy and beautiful addition whether in bloom or not.

Though beardless irises are often called “water irises” and many do grow in marshy conditions in the wild, most varieties do great in regular home gardens. They enjoy a full to partial sun location and a balanced fertilizer in the spring when the plants are a few inches high. Japanese Irises are especially heavy feeders and appreciate a second feeding of fertilizer before bloom time. During dry periods, mulch the roots to help retain moisture.

Japanese Iris ‘Picotee’

If you buy your beardless iris in a pot, it can be planted at any season. Just plant it at the same depth in the garden as it was in the pot. 

If you receive a rhizome by mail order, though, it will likely be shipped in the fall wrapped in damp paper and placed in a plastic bag. Immediately remove the rhizome and soak the roots in water overnight. These roots do not like to dry out, so plant immediately, at the latest about four weeks before the first hard freeze. Beardless rhizomes like to be planted at a depth of 1″ (2.5 cm) (2″/5 cm for Japanese iris).

Beardless irises can grow for many years in the same location. Japanese irises are the exception—they like to be divided every three years.

There are six main types of Beardless Iris.

Louisiana iris ‘Rhett’

The first four types are commonly grown in gardens, and they all bloom late spring and early summer. The fifth type, the Pacific Coast Native, is native to the western regions of the United States and is not as well known. The sixth is Other and includes many of the flag irises seen in the wild.

  1. Spuria Iris (I. spuria), USDA zones 5 to 9
  2. Siberian Iris (I. sibirica), USDA zones 3 to 8
  3. Japanese Iris (I. ensata), USDA zones 4 to 9
  4. Louisiana Irises (I. fulvaI. brevicaulisI. nelsoniiI. hexagona, and I. giganticaerulea), USDA zones 5 to 9
  5. Pacific Coast Natives or Californicae (I. bracteataI. chrysophyllaI. douglasianaI. fernaldii, I. hartwegiiI. innominataI. macrosiphonI. munziiI. purdyiI. tenaxI. tenuissima and I. thompsonii), USDA zones 7 to 10
  6. Other beardless irises (includes yellow flag [I. pseudacorus], blue flag [I. versicolor], rabbitear iris [I. laevigata] and Virginia iris [I. virginica]), USDA zones 3, 4 or 5 to 9

Bulbous Irises

Dutch irises ‘Mount Everest’ and ‘Discovery’

These irises come from drier climates than the others and form a true bulb with a papery outer coating rather than a rhizome. They are generally sold as dry bulbs in the fall, along with tulips and narcissus.

They dry prefer conditions in the summer months, when they go fully dormant, losing their leaves.

There are two main types of bulbous irises.

  1. Dutch iris (I. × hollandica and related species)
  2. Reticulate irises (I. reticulata, I. danfordiae and others) 

Dutch irises are usually sold in the fall, but specially treated bulbs may be available in the spring. Plant the bulbs about 5″ (12 cm) deep with the pointed tip up.

These irises are a popular cut flowers, used by florists in seasonal flower designs. They flower in late spring to early summer and can be grown in sun or partial shade. The bulbs are hardy in USDA hardiness zones 6–9, surviving only sporadically in colder zones. However, even in the best of conditions, they tend to be short-lived, often blooming only once, and are therefore often used as annuals.

Dutch Irises look best when planted in groups. For a stunning show, plant about a dozen bulbs per square foot.

Reticulate iris ‘Katherine Hodgkin’

Reticulate irises are small plants with netted bulbs (that’s what reticulate means) that bloom in earliest spring, sometimes even late winter. They need full sun in spring and dry summer conditions. Most are hardy from zones 4 to 9 and can live for decades, often spreading. They are at their best in rock gardens and garden borders.

Even More Irises

There are many other irises to discover. Once you’ve tried a few of the more common ones described above, you’ll certainly want to get to know even more of the iris world in this, the Year of the Iris!

Unless otherwise noted, all photos are courtesy of the National Garden Bureau.

The Joy of Snowmelt Bulbs

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The very first spring crocuses sprouting in my otherwise snow-covered yard on April 16th!

A lot of people find it hard to believe that there snow is still snow where I live (Quebec City, Canada). And many of you think that snow until the middle of April would be reason enough to move. But you would be wrong. In fact, I get to see a sight few North Americans have ever seen: the flowering of snowmelt bulbs.

Snowmelt bulbs are normally found in the mountains of Europe. Their characteristic is that they start bloom when there still snow nearby. In fact, they sometimes bloom right through the snow. As I speak, the snow banks in my yard are melting back towards the shadier spots, and as they retreat, flowers spring up. Not a few weeks later, or a few days later, but the same day, literally an hour or so after the snow melts. It’s as if the flowers were pushing the snow back, forcing it to retreat.

How is that even possible? How can you go from ice to bloom in just minutes? The amazing fact is that these small bulbs actually grow under the snow. No, I’m not exaggerating. They actually start to sprout under the snow and ice at the end of the winter. So when the snow does melt, their growing point is exposed and they’re immediately ready to bloom.

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Crocus tommasinianus

You can grow snowmelt bulbs just about anywhere that has cold winters, zones 2 or 3 to 8. And they’re usually the first flowers to bloom anywhere you plant them, blooming as early as January in milder climates. But in most climates, they don’t bloom at snowmelt, they bloom a few weeks later. They’ll only bloom at snowmelt in very special climates, like mine, where snow is deep and takes a long time to melt away. This is the case where they grow wild in the mountains of Europe and Asia, and also in the snowiest parts of North America. And it’s not the total amount of snow that counts, it’s how long it takes to melt. Typically here the snow doesn’t melt away until late March or early April, sometimes not until May. And snowmelt bulbs are entirely ready t o bloom by then.

The Best Snowmelt Bulbs

There are essentially four snowmelt bulbs: snowdrops, winter aconites, botanical crocuses and reticulated irises.

Snowdrops (Galanthus nivalis and others)

Snowdrops

Galanthus nivalis

Snowdrops are the best known snowmelt bulbs… and their name even tells you they bloom while there is snow on the ground. Each bulb produces a single flower stem from 4 to 6 inches (10 to 15 cm) high, each bearing a single hanging white flower with a small green-marked crown in the center. Snowdrop flowers may last only a week if the weather suddenly turns hot, but I’ve seen them last a month when the spring was very cold. They clump up nicely over the years, looking better and better over the decades. Zone 2 to 8.

Winter Aconite (Eranthis hyemalis)

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Eranthis hyemalis

This is the least well known snowmelt bulb, but also the most intriguing. You see, it actually melts the snow itself. Yes, the bulb gives off heat as it starts to grow, often creating an effect of a carpet of white dotted here and there with yellow blooms. It’s a very small plant and bears only a single stem coiffed with a collar of green foliage and one bright yellow flower. If the bloom reminds you of of a buttercup (Ranunculus acres), you’re right. The two are the buttercup family: the Ranunculaceae. Zone 4.

Botanical Crocuses (Crocus spp.)

There are actually quite a number of snowmelt crocuses, but only a few are commonly grown. Here are the most common ones, roughly in order of flowering, from earliest to last… although that may only a case of a couple of hours difference!

Golden Bunch Crocus (C. ancyrensis): produces a dense cluster of small, bright yellow flowers. You can tell it from the golden crocus (see below) by its pure yellow color. Zone 4 (3 under snow cover).

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Crocus sieberi sublimis ‘Tricolor’ growing in my lawn.

Tricolor Crocus (C. sieberi sublimis ‘Tricolor’): each flower really does show 3 colors! The flower is bluish purple with a broad orange throat and, between the two colors, a distinct band of white. Zone 4.

Tommie Crocus (C. tommasinianus) larger flowers than the other snowmelt crocuses and the only one that spreads readily in the garden, self-sowing gleefully when it is happy… and I’m certainly not the person who’ll try to stop it. As far as I’m concerned, you can’t possibly have too many crocuses! The base flower color is lavender with a darker edge, but there are a several common cultivars in various shades of violet end purple. Zone 3.

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Mixed Crocus chrysanthus in a lawn.

Golden Crocus (C. chrysanthus): the species has yellow flowers streaked with brown on the outside, but there are many cultivars of different shades of yellow, purple or white flowers, most showing purple or brown stripes on the outside. Zone 3.

All these snowmelt crocuses bloom about a week earlier than the much more popular Dutch crocus (C. vernus) which has larger flowers.

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Iris ‘Katharine Hodgkin’

Reticulated Iris (Iris reticulata and its hybrids and relatives): The flowers are huge for such a short plant and and actually very typical of an iris: you really couldn’t mistake it for anything else. They come in various shades of purple, purple and white. Of this group, the most spectacular and earliest is I. ‘Katharine Hodgkin’ with flowers best described as turquoise: what a stunning plant and oh so easy to grow! Zone 4.

The “Après Snow” Bulbs

There are other bulbs that bloom just a little later then the snowmelt bulbs (puschkinias, Greek anemones, glories of the snow, bulbocodiums, some of the earliest narcissus, etc.) and I strongly recommend planting some of them as well. But they only bloom once all snow is gone and therefore are not, according to my definition at least, snowmelt bulbs,

Mark Your Agenda!

20150518HOn of the unfortunate facts of gardening life is that when plants are at their most beautiful is usually not the best time to plant them. And early spring flowering bulbs need to be planted a good 5 to 7 months from now, in the autumn. So while you may have spring blooms on your mind right now, you’re likely to have forgotten all about them by fall. That’s where an electronic agenda comes in handy.

Who doesn’t have an electronic agenda today? On your smart phone, your tablet, your computer, etc. So, before you even finish reading this paragraph, write down “plant snowmelt bulbs” on your agenda somewhere in mid-September. If not, you’ll almost certainly forget to plant them and so will miss the very first flowers of spring. If that isn’t tragic, I don’t know what is!

Of course, while you’re at it, you can plant a whole range of other spring-blooming bulbs at that same season: tulips, daffodils, hyacinths, etc. With a careful choice of snowmelt bulbs, early bulbs, mid-season bulbs and late bulbs, you’ll gain a good 2 months of bloom. Just make sure to include a few of the earliest bulbs to your plant list for those ultra-early blooms.

Growing Snowmelt Bulbs

Honestly, is there anything easier? Just plant the bulbs at a depth equal to three times the bulb’s height from mid- to late September. Try not to be later than that, as some of these very small bulbs, and especially winter aconites, tend to dry out and die if they’re aren’t planted fairly rapidly. You can plant them in a flower bed or a rock garden, remembering they need full to half sun… spring sun, that is! If the spot will be shaded later by overhanging foliage, that’s of no importance, as these bulbs will be dormant by then. Also, well-drained soil is a must. Unlike tulips, small spring bulbs really don’t need much in the way of fertilizer and will come back annually for decades. You can also naturalize them in a lawn (that’s what I do at my place). Simply lift the sod, place the bulbs in the hole and put the sod back in its place. And the last step when you water anything is to water well.

Once in the ground, snowmelt bulbs require no special care. Just let Mother Nature take care of them. You don’t have to deadhead and the foliage will fade away all on its own. If you have naturalized some in a lawn, just mow it as usual: by the time the lawn needs mowing, the snowmelt bulbs’ foliage will be long  gone and they will be fully dormant under the ground where the lawn mower can’t hurt them.

So, snowmelt bulbs: easy to grow, inexpensive (did I mention that?)… and you’ll have the first flowers on the block. Make next spring the best one ever!