Is There Life After Bloom Season?

by Tom Waters

Although I am an unabashed iris enthusiast and grow a garden that is dominated by irises, I want an outdoor space with more than just rows of irises. In particular, I like my garden to be a pleasant and interesting space to sit in or walk through, any time of the year. So over the years, I have acquired a collection of mostly care-free plants that flower during the months when the irises are not in bloom. I live in the arid southwestern US although at an elevation (6000 feet) that keeps us a little cooler than the true deserts of this region. My location is in the United States Department of Agriculture plant hardiness zone 6a. 

Although most of the plants I describe in this article will be happy in most of the western US, this post is not really intended as a plant list, but more as a recounting of how I have gone about making my outdoor space a garden that features irises, rather than just a giant iris planting. If you share that goal, I hope that you will pick up a few ideas as you read on.

Although I love to read books and watch television programs about garden design, I confess I am not the type who plans a garden on graph paper and then goes out to buy the plants. Rather, I create the garden first, try lots of different things as I think of them, and then see what works. If I like how something turns out, I do it more. In this way, the garden is more the result of evolution and editing than of advance planning.

My iris bloom season is centered in May, and the tall bearded bloom extends into June. I grow many plants of Iris pumila and other dwarfs, which start blooming early in April or at the very end of March. Spring bulbs are of course the obvious way to beautify the garden before the bearded iris bloom season. I gravitate toward daffodils and crocuses, rather than the more formal bedding bulbs such as hyacinths and tulips. I like bulbs that can be scattered around and surprise me when they come up. Although I like the smaller botanical crocuses, I confess that the Dutch giants are really the only ones that make much of an impact here. I do pay some attention to color: the yellow ones are mostly in a bed along the driveway, whereas the quieter garden in the back yard is given over to the white and violet crocuses, and white ‘Thalia’ daffodils.

True geraniums, columbines, and blue flax all start blooming during iris season and continue on for months afterwards. The geraniums need some room to themselves, but the flax and columbines are airy enough that they can live amongst the irises without crowding in on them. The columbines are in only a few places, as they require some shade here. The blue flax is an amazing plant, with long arcing stems and beautiful spectrum-blue flowers. It keeps blooming right through the summer and into autumn. Blue flax seeds itself, so after a few years it will be anywhere in the garden that I want it to be (with no attention or extra effort on my part).

I grow a few daylilies too, as they are showy and bright. I have heard some people recommend not to mix daylilies and irises, since the irises don’t like as much water as the daylilies need. Frankly, in my climate, it’s almost impossible to give irises enough water to bother them. Mine do fine together!

I have a couple very aggressive self-seeders that I enjoy: Mexican feathergrass (Nasella tenuissima) and clary sage (Salvia scarea). The feathergrass ripples in the wind and adds interest to the landscape all year round, since the leaves look nice even when dry over winter. The clary sage blooms profusely as the irises are finishing, through July, and the dried seedheads also look nice through the autumn and winter. Bumblebees and hummingbird moths love them, and we get little birds who come in large numbers to peck around for their seeds. Some people can’t abide aggressive self-seeders, but I don’t really mind. It’s not like you can stop weeding the garden if you don’t grow these things! Since I’m weeding regularly anyway, it makes no difference if I am pulling up these guys rather than something else that would be there instead. The trick is to get used to how they grow and not be taken by surprise. They can seem innocent while young, but that is when you have to be ruthless if you find them in a spot where they will be unwelcome when fully grown.

Last year, I grew a stand of showy milkweed (Asclepias speciosa), thinking to do my bit to help out the monarch butterflies. I completely misjudged how big these things get! I love them, though, both the flowers and the raucous cotton-candy like seed heads. This year, they are getting some severe editing. I will restrict them to areas in the back of the bed, behind the irises, not amongst them!

Fallugia paradoxa and Penstemon eatonii

Speaking of seed heads, I somehow managed to live my whole life in New Mexico without noticing Apache plume (Fallugia paradoxa) until seeing it at a native plant society gathering a few years ago. Now I am in love! This is a shrub that can grow quite large. It displays simple white flowers late in iris season, followed by pinkish, feathery seedheads that persist until frost. It’s a native here, and requires no care at all once established. With very few exceptions, this is one of my rules: I water and weed the iris beds routinely, but any plant that needs special attention beyond that doesn’t get a place in my garden. I’ll try any plant once; a few might earn a second try, but after that they are off the list.

I also grow quite a few different penstemon species. Most bloom at the end of iris season or shortly afterwards and their flowers last maybe a month or so. Some penstemon species bloom longer. Red ones are pollinated by hummingbirds, although I have seen hummingbirds enjoying the violet ones too.

Most of the other plants in my garden look their best in early summer, and the garden tends to ramp down as the year progresses. My favorite autumn-blooming plants are the hylotelephiums, such as ‘Autumn Joy’ and its ilk. I need to remind myself to get more of these. I have only a few in one spot, but could enjoy them in lots of other places.

One of the consequences of not doing advance planning is that you can end up with “holes” – periods of time when there’s not much in bloom and the garden seems on hold. One solution is to stay alert for this; and when the lull comes around, go visit friends’ gardens and local nurseries and see what looks good. Even if you don’t buy them right away, you can record which plants could be introduced to fill the gap.

I don’t put a lot of effort into finding plants that bloom in autumn. Summers here are hot and dry, and everything gets stressed. By the end of the season, both garden and gardener are looking ahead to the peace of winter, rather than seeking to recreate the exuberance of spring and early summer. I do, however, love the autumn crocuses (Crocus speciosus), which pop up suddenly after a rain and give a final burst of color as the gardening year winds down.

With a little experimentation and some time, it is possible to have a garden that is mostly irises but still holds interest and looks nice year round. Even iris nuts deserve a pleasant outdoor space!