The First Irises of Spring

Expect the spring’s earliest irises—the netted irises or reticulated irises—to appear shortly after snow melt. Photo: www.webbsdirect.co.uk

If you’ve been out shopping over the last few days, you already knew this, but if you haven’t, be forewarned, “fall bulb season” is now underway. Garden centers, box stores and even supermarkets are full of striking, eye-catching packaging containing bulbs to plant in the fall. If your only experience with the phenomenon is the rather meager display found in a supermarket and or big-box store, however, get thee to a garden center: the choice is so much better! I don’t know how any gardener could resist!

But why at this time of year? That’s because it’s the bulbs you plant in the fall that supply the garden in spring color. Without bulbs, our flower beds would be nearly empty for the first 2 months of spring. With a careful choice of bulbs, including very early, early, mid-season and late bulbs, however, you can ensure non-stop bloom from snow melt to the first hot days of summer.

The Dwarf Irises of Early Spring

It would be impossible to present all the flower bulbs which are currently on sale, but since this is 2020, the Year of the Iris, let’s focus on one single category: netted irises.

Tall garden irises are better known to most gardeners: bearded irises (Iris × germanica), Siberian irises (I. sibirica), blue flag irises (I. versicolor), etc. With their tall flower stems and multicolored flowers (“iris” means rainbow), they decorate our gardens in early summer, but before that—long before!—, another kind of iris is the star of the garden, a small iris barely 6 inches (15 cm) high.

Unlike tall garden irises, which grow from either fibrous roots or rhizomes, these small spring irises are bulbous plants. Their tiny, teardrop-shaped bulbs are covered in what looks like golden netting. This called reticulation, hence the name reticulated iris (Iris reticulata) for the most common species. The term netted iris is also used and that’s the term I’ll be using. These netted irises form a subgenus within the genus Iris of the Iridaceae family: the Hermodactyloides.

Another curious feature of netted irises is their rigidly erect, narrow, 4-angled leaves: yes, they’re square in cross-section! The leaves are borne two to four per bulb.

You plant netted iris bulbs in the fall. In the Northern Hemisphere, between September and the onset of winter. They then flower early in the spring, even in late winter in milder climates. I can’t give you a precise date, as when they actually bloom depends on winter in your area, but these little irises are always among the first flowers of spring, just after the snowdrops (Galanthus). In fact, when they bloom, there is often still snow in the background!

So Much Choice!

There are dozens of varieties of netted irises, but the choice you find locally will probably not be that complete. To start with, supermarkets and box stores often don’t offer them at all: they stick to the standard tulips, daffodils, hyacinths and crocuses. However, a good garden center should have at least a few varieties of netted irises. And if that isn’t enough (and it certainly isn’t for me!), go online and start flipping through the bulb catalogs: that’s where the real choice is found. I discover new varieties every single year!

To make some sense of the netted iris group, I find it useful to divide them into 3 categories.: the blue netted irises, the yellow netted irises and the hybrid netted irises, the latter being, of course, the result of crosses between the first two categories.

Blue Netted Irises

The group of blue netted irises consists mainly of two species which are very similar and indeed, often confused: the true reticulated iris (Iris reticulata), by far the most common, and the winter iris (I. histrioides). There are also a few other blue netted irises, like the Syrian iris (I. histrio), mainly used in hybridizing. Their main feature is that they produce surprisingly large flowers compared to their overall size. To give you an idea, the plant rarely measures 6 inches (15 cm) in height when in bloom, yet the flower is 4 inches (10 cm) in diameter! The flowers are also fragrant, but you have to bend way down to smell them.

Blue netted irises come in the full range of shades of blue and purple, from dark to light and some have white flowers as well. In addition to their base color, the flowers are always marked with yellow and white. Over time, the number of bulbs increases and so does the number of flowers. These irises are suitable for hardiness zones 4 through 9.

As mentioned, there is considerable confusion as to which cultivar belongs to I. reticulata and which are I. histrioides. My guess is most of the cultivars are hybrids of the two … but I’ll leave nit-picking over plant names to the experts. I simply followed the usage found in most catalogs in preparing the following list.

Among the cultivars are:

I. reticulata ‘Alba’: white, orange accents.

I. reticulata ‘Alida’: blue with yellow crest.

I. reticulata ‘Cantab’: flax blue, orange accents.

I. reticulata ‘Harmony’: royal blue, yellow accents. Popular variety with proven results.

I. reticulata ’J. S. Dijt’: deep purple red, yellow accents. Another very popular variety.

I. reticulata ‘Joyce’ ?: dark sky blue, yellow accents.

I. reticulata ‘Natascha’: very light blue, nearly white. Pretty and original!

I. reticulata ‘Pauline’: dark pinkish purple, white accents.

I. reticulata ‘Springtime’ (SpringTime’): pale blue standards, dark purple-blue falls.

I. histrioides ‘George’: Velvety dark purple.

I. histrioides ‘Frank Elder’: white to pale blue, yellow and green markings.

I. histrioides ‘Lady Beatrix Stanley’: medium to dark velvety blue, yellow and white markings.

I. histrioides ‘Major’: larger than the others, dark blue flower marked with white.

Yellow Netted Irises

There is actually only one commonly available species of yellow netted iris: Danford’s iris (I. danfordiae). Its flower is a little smaller than the others, and so is the plant (it measures only 4 to 5 inches/10 to 12 cm in height) and it blooms a day or two earlier than the other dwarf irises. Also, the leaves appear after the plant blooms (in blue netted irises, the leaves appear during flowering). The flowers are sulfur yellow with darker spots on the blade.

Danford’s iris tends to flower only once and then divide into several smaller bulbs which then don’t flower for several years. One trick that can help make it a perennial bloomer is to plant it deeper than the other netted irises, about six inches (15 cm) deep. As with tulips, deep planting helps prevent the proliferation of offsets and allows the main bulb to bloom annually. Zones 4 to 9.

The other yellow netted iris, I. winogradowii, is seldom commercially available, but has been used in hybridization.

Hybrid Netted Irises

This is where things start to get really interesting! This hybrid group is a fairly new category of netted irises with some startling color combinations. This results in unique color combinations of blue, yellow and other hues.

I. × ‘Katharine Hodgkin’: In my opinion, this iris is the best of all the netted irises. It blooms abundantly and increases rapidly in the garden under average conditions: a planting of 10 bulbs can give, in 3 or 4 years, a mass of more than 100 flowers! The flowers are pale blue with an overlay of pale yellow and many thin blue stripes, giving an almost turquoise effect! Very, very easy to grow. Zones 4 to 9.

I. × ‘Katherine’s Gold’: New to me (I’m waiting for the bulbs to be delivered as I write this), it’s a sport of ‘Katharine Hodgkin’, so I’m hoping it will be similar in behavior. The color is quite different, though, with very pale yellow flowers accented with blue. Charming! Zones 4 to 9.

Canadian Hybrids

Toronto-based hybridizer Alan McMurtrie has been working on netted iris hybridization for over 30 years and has created phenomenal hybrids, often of unique colors. However, they seem less hardy than the other netted irises: perhaps zones 5 to 9. They need a good mulch if you plan growing them in zone 4.

I. × ‘Eye Catcher’: White, cobalt blue and yellow.

I. × ‘Happiness’: Bright yellow with green highlights and dots of green.

I. × ‘Mars Landing’: Dark brown with yellow highlights. This didn’t look as good in my garden as in the photo. I might try surrounding it with a pale mulch so it stands out better against the brown spring soil.

I. × ‘North Star’: Buttery yellow and creamy white with blue-green spots.

I. ×‘On Cloud Nine’: White flowers dotted with sky blue, yellow central stripe.

I. × ‘Orange Glow’: Orange and yellow with a black line.

I. × ‘Scent Sational’: Dark purple blue with yellow and white markings. Very fragrant.

I. × ‘Sea Breeze’: Royal blue, white and yellow. Striking!

I. × ‘Splish Splash’: Royal blue streaked yellow and heavily marked with white spots.

I. × ‘Spot On’: Royal purple flower with white marked falls.

I. × ‘White Caucasus’: White flower with a yellow stripe. Considered by some to be the best of the white netted irises.

The Canadian hybrids are very new and not necessarily widely distributed. Also, they’re still quite expensive. I buy mine at Phoenix Perennials, a company that ships to Canada and the United States. In Europe, try J.Parker’s Ducth Bulbs for a wide choice of netted irises, although they don’t carry many Canadian hybrids yet.

Don’t Confuse Your Irises

Warning! There is another bulbous iris that is sold in the fall: the Dutch iris (I. × hollandica). It’s popular with florists and is widely grown in greenhouses as a cut flower. However, pretty though it may be, it’s not the best garden iris. In fact, it’s usually treated as an annual.

Also, it’s not nearly as hardy as is usually claimed. It’s probably reasonably hardy in zone 6 and more strongly hardy in zones 7 to 9, but I keep seeing it labeled as hardy to zone 4! That’s not a problem in most of Europe and in the American South, where winters are mild, but it’s annoying in colder climates. I mean, when you pay for 10 bulbs, you should get 10 flowers, not only y 2 or 3 that somehow survive the cold.

Hey bulb growers: you really should mark the right zones on your packaging!

Of course, even though Dutch irises are not the best garden irises, they do make great choices for forcing.

So, how can you tell the two apart? First, most packaging will indicate “reticulated iris” or “Dutch iris”. But if not, remember that netted irises are small (about 6 inches/15 cm tall) while Dutch irises are tall (20 inches\50 cm and more), a detail that always appears on the packaging.

Planting and Caring for Netted Irises

Nothing could be easier than planting netted iris bulbs. Choose a location with very well-drained soil that will be in the sun in the spring (netted irises will be dormant in the summer and won’t be bothered by summer shade), then dig a hole 4 inches (10 cm) deep. Sprinkle some mycorrhizae (beneficial fungi) in the bottom of the hole and place the bulbs about 5 to 6 inches (12 to 15 cm) apart, pointed side up. Then fill the hole and water.

There is no need to worry that animals like squirrels will dig netted iris bulbs up or that deer will eat the flowers in the spring: they simply don’t like irises!

No special care is needed in spring, when the plant blooms. After flowering, you will be surprised to see the narrow leaves, short or absent during flowering, quickly rise to 10 to 14 inches (25 to 35) cm in height. They disappear after a few weeks, as the bulb goes dormant for the summer. If you have to move or divide the iris bulbs, that would be the right time to do so. Just replant right away; no need to store them out of the soil over the summer.

Now, there is one vital thing to remember. Netted irises don’t like wet summers, but prefer passing their summer dormancy on the dry side. That’s why well-draining soil is so important. They don’t like clay soils and irrigation systems, which always seem to leave gardens practically soaking, are an anathema to them. Bulbs kept too wet tend to rot. So … place netted iris in the drier parts of your garden!

Forcing

I don’t want to get into all the details of forcing bulbs here, which I see as a very different subject. Suffice it to say that netted irises are easy to force. You can read more on forcing bulbs in the article Forcing Bulbs Without Twisting Arms.

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Spectacular flowers that require so little effort and cost so little (well, at least that’s the case with the older hybrids)? Don’t be shy about planting these little irises in large quantities! They can really make your spring come alive!