Pacific Coast Native Iris by Harry Hill

You have probably heard the old expression that good things come in threes. Well, for me nothing exemplifies this better than the flower of the iris. It’s all based on threes – three falls, three standards, three style arms – and yet expresses an amazing variety in colour and texture within that simple pattern. In the gardening world, the big flouncy blooms of tall bearded iris have long been the image that comes to mind when we think of iris. Native to open country in warmer, drier climes than the Sunshine Coast, their rhizomes invariably succumbed to rot in my winter-wet garden. The Siberian iris that I tried next were infinitely tougher and better adapted to our local conditions. More importantly, they hinted at the wide world that exists beyond bearded iris.

While visiting the May garden of my neighbour Vonnie Kovacic about eight years ago, I noted a rather diminutive, orchid-like flower that could only be a type of iris. Vonnie said if I could guess what it was, she would give me a piece of it. Although I had only read about them before, never actually seen one, I guessed that it might be a Pacific Coast iris. It was, and true to her word, Vonnie gave me a section of this wonderful plant, which has since thrived in my garden and been passed on to friends. It’s an unnamed hybrid seedling, but I like to think of it as ‘Vonnie’.

 

After that introduction, I began to read up on Pacific Coast iris (PCIs) and eventually obtained seed from the seed exchanges of the Alpine Garden Club of B.C. and the Society for Pacific Coast Native Iris. My enthusiasm for these iris came about partly through an interest in growing West Coast native plants – low-maintenance species that are naturally adapted to our cool, wet winters and temperate, dry summers – and partly because of their unique beauty.

Unfortunately, none of the species in the Californicae series of the Iris genus make it up as far north as B.C. (Iris setosa occurs in the northwest of the province, and I. missouriensis in the southern Interior). The range of the most northerly PCI, Iris tenax, falls just short of Tacoma, Washington, which is only marginally warmer than the Sunshine Coast. Although Iris tenax might be the most cold hardy PCI, B.C. iris growers I’ve spoken to have all cited I. douglasiana as being more tolerant of the high winter rainfall and heavy soils of most coastal B.C. gardens. Only those gardening in gritty, fast draining soil thought I. tenax was a better choice.

Iris douglasiana (Douglas iris), I. innominata (golden iris) and I. tenax (Oregon iris) are the three mostly commonly grown Pacific Coast species. They are available from several native plant nurseries in the province, but not through the general nursery trade. Some B.C. gardeners have ordered named hybrids from U.S. mail order nurseries, but the unfavourable exchange rate and additional phytosanitary and shipping expenses can be discouraging, not to mention delays at Canadian customs that threaten the viability of the rhizome divisions.

The 11 species of Pacific Coast iris cross with each other in nature, as well as in the garden. Iris breeders have been able to exploit this trait to create hybrids that combine the most desirable features of species and individual plants:

• branching stalks that carry several flowers
• broader petals and a wide colour range
• longer blooming season
• evergreen, straplike foliage
• clumping habit

Nearly one thousand PCI varieties have been named, introduced and registered during the past few decades. Colours are extremely variable, including reds, yellows, browns, grey, blues, purples, pinks and cream. The falls and standards are sometimes different colours, or are streaked and veined in a darker shade. Individual plants bloom for three or four weeks; on the Sunshine Coast, the bloom period lasts from the last week of April to the first week of July. Hybrids can range from 15 to 50 cm in height.

In choosing a site for Pacific Coast iris, the most important factor to bear in mind is good drainage. You might want to amend your soil with sand, grit, peat and compost to improve their root run and to facilitate drainage. In coastal B.C. PCIs seem to flower best in full sun, although they will tolerate light shade. Some watering is beneficial during our summer ‘drought’ period, and this is best done in early morning or evening.

PCIs eventually form broad clumps and can be quite eye-catching when in full bloom. They combine well with low growing ornamental grasses, heuchera and pulmonaria. I also like to fill in the gaps in summer with colourful West Coast native annuals like clarkia (Clarkia amoena and C. unguiculata), Chinese houses (Collinsia heterophylla) and California poppy (Eschscholzia californica) by sprinkling a few seeds between the iris clumps in fall or early spring.PCIs resent being divided yearly; it is best to let them grow undisturbed for a few years. If you have a plant that is especially beautiful and would like to share it with a fellow gardener, carefully cut out one section of rhizomes and leave the remainder intact. Transplanting is usually done in spring or fall, when the roots are plump, white, and actively growing. I’ve had the best luck in early to mid-October. Try to avoid damaging the roots and keep as much soil as possible around the sections you’re transplanting. Once in the ground, they should be watered immediately and kept moist until they are well established.

 

Pacific Coast Iris from Seed Pacific Coast iris have a poor survival rate when they’re shipped as bare root divisions, so it’s fortunate that they’re very easy to start from seed. The other good news is that almost every seedling is attractive. Sow the seeds as early in fall as possible, using pots or flats filled with a peaty soil mix that is one-third sand, perlite or chicken grit to improve drainage. Cover with about 1 cm of mix. Plant as many seeds as you can physically separate from each other when it is time to transplant them (2 to 3 cm apart). Place in a cold frame or greenhouse and keep the soil evenly moist. The seeds will germinate in late February or March and resemble blades of grass at first. Transplant the seedlings to the garden or into pots when they reach about 10 cm tall. This will generally be May or early June. If pots are your choice, use a 4-litre (one-gallon) pot for each seedling. When planting directly into the garden, select a spot where they won’t be crowded out by competing plants. I’ve had most success keeping them potted and protected in a cold frame over their first winter, and then planting them out the following spring when the soil warms up. Pacific Coast iris transplant well as seedlings, and will bloom their second or third spring. Established plants are drought and frost tolerant.

Harry Hill’s enthusiasm for Pacific Coast iris is bordering on a gardening obsession – he has dozens of species and cultivars in his Roberts Creek garden, with hundreds more hybridized seedlings on the way. Harry is the Canadian representative for Almanac, newsletter of the Society for Pacific Coast Native Iris.

Click HERE for more photos of Harry’s Pacific Coast iris.