The Dry Succession Garden

PART ONE

My primary study in gardening is the creation of successional planting schemes for mediterranean-climate types. Succession planting is the layering of plants to create dramatic change in the garden over the growing season, and to extend bloom over a long period. This has long been part-and-parcel of gardening in cold climates; the real winter dormant period and the subsequent gradual unfolding of the seasons allows for gardens that look completely different from one month to the next, from the procession of bulbs in late winter into spring to towering perennials and ornamental grasses in late summer. Successional planting schemes are primarily accomplished through the use of bulbs, grasses, and herbaceous perennials.

Great Dixter Long Border in May and October
From Christopher Lloyd’s Succession Planting for Year Round Pleasure, 2005.

The late Christopher Lloyd, of Great Dixter, wrote a five-part series on succession gardening in his column for The Guardian in 2004:

With our sights always focused on getting best value over a long season - the ethic of "I'm not greedy but I like a lot" - we constantly plan so that two plants of different seasons can share the same space without getting in each other's way. Bulbs are often ideal for this purpose. Most will flower in spring before deciduous shrubs, and before many perennials have rubbed the sleep out of their eyes and become active. Crocus tommasinianus, say, will flower in February; it self-sows and will make a colony among the stems of the suckering dwarf almond, Prunus tenella, or around the crowns of the August-flowering willow gentian, Gentiana asclepiadea. The prunus will flower in May and the gentian in August. (Lloyd, 2004)

And this style of gardening is not just for experts. Amateur garden books for cold climates from the last century have invariably had a chart indicating bloom time of various bulbs and how to arrange them in succession. The majority of these bulbs/geophytes - Crocus, Colchicum, Iris, Narcissus, Tulipa, Fritillaria, Allium, Sternbergia - all have a significant number of species hailing from mediterranean-climates. It’s surprising they are not commonly utilized in California gardens; far more of these species are grown in English glasshouses and windowsills than are grown in California, where they are adapted to grow outdoors and could provide a basis of succession in our gardens.

An ad for Sternbergia lutea from a Massachusetts nursery in American Horticulturalist, August/September 1979
and Sternbergia lutea growing wild in Mallorca, Spain, a similar climate to Los Angeles
Photo: enbodenumer (Flickr)
https://www.flickr.com/photos/enbodenumer/

Attempting these sorts of plantings in California is not a new idea. Expert gardeners such as Chris Rosmini and Kate Frey have created gardens in California primarily utilizing bulbs and herbaceous perennials focusing on dynamic change across the season. In the Fall 1984 edition of Pacific Horticulture, Chris Rosmini detailed:

Some good plants wouldn’t bloom or look good for a long enough season to list but for their willingness to time-share space in the garden, either by one plant growing through the other and both blooming together, such as Verbena rigida and Convolvulus mauritanicus, or by one plant replacing the other completely. Alstroemeria ligtu hybrids come up through the early foliage of Physostegia virginiana, flower in early summer and disappear completely in time for the physostegia to put on a display in August. Ceratostigma plumbaginoides has intense blue flowers in fall, after which the twelve-inch stems turn brilliant red and die back completely, leaving space for sprawling winter bloomers such as Euphorbia rigida. (Rosmini, 1984)

Similarly, Kate Frey’s garden for the Fetzer Vineyard in Hopland, CA (now sadly gone), was a beautiful take on the English border using heat-tolerant herbaceous plants to stunning effect.

Kate Frey’s former Fetzer Vineyard garden, Hopland, CA
Photo by Kate Frey
http://freygardens.com/?page_id=802)

To accomplish this type of garden, the planting requires a period of dormancy, a starting point to succeed from, something for the plants to wake up from. This can take two different forms: 1) choreographing the individual dormant periods of plants from varying climates, and irrigating them per their individual needs, such as in Kate Frey’s Fetzer Garden or Chris Rosmini’s planting she describes above, or 2) choreographing a group of plants all responding to the same climatic period of dormancy  – i.e., winter in cold climates, summer in mediterranean climates.

My next post will detail a succession technique to use plants from varying climates à la Rosmini, but for now I will focus on the fully dry garden in a mediterranean-climate context. My primary objective is always to create gardens that feel truly alive, and when irrigation is added I can’t help but feel the plants are on life support; they are not responding to the vagaries of weather and climate, bursting into growth with the rainy season, or browning and dwindling with drought, but instead are simply kept alive in a sort of state of suspended disbelief. However subtle, you can tell something is amiss in the garden. The irrigated perennial garden, while beautiful, still has a hint to me of something superficial, more a novelty of plant obsession than a natural wonder. When spring and summer hit in a cold climate, the bounty of nature in response to climate is truly palpable – everything feels abuzz with life. Similarly, when a garden has been dormant all summer, the eruption of a field of Crocus goulimyi with the first rain starts to mean something, starts to feel expansive and connected and whole.

Los Angeles typically experiences six months without even the slightest rainfall, usually from May through October. Not only on “drought” years, but as a natural seasonal state. This is our equivalent of winter. The desire to irrigate in this period is certainly understandable; while winter in cold climates is expected to be bleak and dreary and plantless, summer in hot mediterranean climates, our equivalent dormant period, does not have the same public acceptance. The imperative to enjoy summer is a strongly rooted cultural idea across climate types, making our natural dormant period hard to contend with. With the simple solution of irrigating, it seems an obvious fix. 

People in cold climates accept their winter dormant period because they have to. Yet what occurs is a communal joy at the return of life after the dormant period, and a shared joy in gardening and how the garden unfolds after the hard days of winter. While aesthetic gardening (rather than food gardening) may have originated as a luxury practice, it is my belief that it has endured because of a need for it, not a luxury. It is a matter of survival; by celebrating the growth and life of the natural growing season you are able to survive the harsh cold and dark days of winter. 

Pulsatilla grandis blooming on a cold April day in Peter Korn’s garden, Eskilsby, Sweden, 2017 (author photograph)

In my interactions with cold climate gardeners I have found an immense generosity; cold climate gardeners survive on hundreds of years of shared knowledge to ever expand upon the creation of beautiful gardens. It is not a competitive business, it is a communal experimentation, a worldwide gathering of information, season after season, to share in the joy of growth and nature and to create a stockpile of that same joy to tide you through the difficult winter.

Gardening in Los Angeles, on the other hand, is a surprisingly lonely business. There is a general love of plant life among the populace, and a satisfaction with the exoticism of the overall urban plant landscape, yet by removing gardens from the natural seasons of Los Angeles by using irrigation, there is no need to celebrate the return of growth after the dormant season and no need to have a shared garden culture. With irrigation, the growing season in Los Angeles reaches almost 12 months, and you'd think the year-long ability to be in the garden would make for an ebullient and exciting garden world. And in the early days of horticulture in California, when everything was new, it was. But until recently, it has led to a ceasing of experimentation. Instead you have a perpetual, muted spring, never really changing, with an ever-present hint of stagnation, where plants start to seem lifeless - interesting sculptures and textures but devoid of seasonal growth and movement, something akin to the Rem Koolhaas quote “Junkspace is like being condemned to a perpetual Jacuzzi with millions of your best friends.” (Koolhaas, 2001)

Yet we do have our own seasons, our own dormant period, our own hardship to overcome with the communal support and joy of gardening. So much so that the origin myth of seasons, still thought of today to describe cold climate winter, Persephone’s abduction into the underworld, was likely conceived to describe the summer dry season as experienced in Greece.

Not irrigating through the dry summer months makes things difficult, a hardship to endure. Our gardens will look brown and dry and a bit sad perhaps. But with this, the return of growth with the winter rains becomes a grand thing to look forward to and be celebrated. And what is more, it challenges gardeners to find ways to make this dormant period beautiful, just as cold-climate gardeners have excelled at in recent years and captivated the world.

Piet Oudolf garden in Stoke-On-Trent, England
Photo by Piet Oudolf
https://www.nytimes.com/slideshow/2011/02/10/garden/20110210-garden/s/20110210-garden-slide-BAUF.html

PART TWO

Once you decide on the value of dormancy, one has to choose what types of plants you will utilize in the dry garden. The preeminent dry gardener, Olivier Filippi, states this should be primarily accomplished through the use of shrubs and sub-shrubs – plants that give an architecture to the garden even in dormancy. Any trip to the Mediterranean proves the worth of these shrub-based gardens - a true sense of calm and coolness can be created through the use of just a few well-placed Myrtles and Boxwoods (greatly helped by old limestone walls and fountains). One can also accomplish beautiful floral/color displays as well, as Olivier and Clara Filippi have expertly proved in their nursery demonstration garden in Mèze, France.

La Louve Garden, Bonnieux, France
Photo: Eva Contreras
http://www.cafedesign.us/la-louve/

Olivier & Clara Filippi’s dry demonstration garden, Mèze, France, May 2017 (author photograph)

Using primarily woody shrubs and sub-shrubs makes sense ecologically, as many mediterranean-climate plant communities consist primarily of woody shrubs. The characteristic mediterranean-climate ecoregions of the world - Chaparral of California, the Garrigue of Southern France, the Fynbos of South Africa, the Matorral of Chile, and the Mallee of Australia - all are dominated by woody shrubs rather than herbaceous perennials.

In the natural areas surrounding Los Angeles, it is only when the landscape is disturbed, especially through fire, that we see an eruption of herbaceous perennials, bulbs, and annuals approximating a typical perennial garden. These plants comprise a natural succession - early annuals and herbaceous perennials (especially pea family plants such as Lupinus sp., Acmispon glaber) colonise a newly sunny site, enriching it’s soil with nitrogen. The soil improves and the plant community starts to return, shrubs resprouting and reseeding, and then later, trees. It is here that I think home gardens should take precedent. What is a garden site, if not disturbed? Any urban or suburban yard soon to be garden has long been changed - native plants denuded and the native topsoil flattened with tractors or completely covered and replaced by fill soil from house construction excavation, the natural drainage of rainwater completely altered. Perhaps before we install our garden of climax-species shrubs (i.e., Arctostaphylos sp.) and large trees (Quercus sp.), we should dwell for at least a little while in the moments of early natural succession, with annuals, perennials, and bulbs/geophytes taking central stage.

This is not to say that shrub-based gardens don’t have their place. It is hard to look at Filippi’s garden and La Louve and not question my whole perennial-focused trajectory. But at this point I’m seeking dynamic plantings that change significantly from one month to the next, and a more severe connection to seasonality and climate.

Ehrendorferia ochroleuca and Phacelia grandiflora in Agoura Hills, CA, post-Woolsey Fire, June 2019 (author photograph)

Delphinium cardinale in the Cajon Pass, one year after the Blue Cut Fire, June 2017 (author photograph)

Castilleja sp. and Lupinus sp. in Agoura Hills, CA, post-Woolsey Fire, April 2019 (author photograph)

So what would a dry succession garden composed solely of herbaceous perennials, grasses, annuals and geophytes in Los Angeles look like? I have devised a simplified collection of plants towards this end for the purpose of starting the conversation. I have tried to select plants here that are commonly or at least sometimes available in the California nursery trade. For now this scheme will mainly be expressed in drawings, but I will post more as my gardens progress.

I have broken down the planting into nine key periods of the year in order to describe the changes in the garden, beginning with the cutting back of the garden in the October.

OCTOBER

In October, with no rain since May, most of the plants in the garden have all withered. Only a few plants continue to look good - Zauschneria canum, Lepidium montanum, the golden hues of various dormant Stipa species (I’m sure there are many more - but these three stand out in my experimenting).

At this point I cut all of the plants in the garden to the ground, to make room for the fresh foliage to emerge once the first rain arrives. This leaves the garden as an open plane, the perfect time to plant new bulbs and plants between the existing stumps, right before the rains commence. I usually leave some of the dry bulb stalks in place until I add more bulbs, to remind myself where they are hiding underground.

I love this period. It is a fresh start from the previous year, filled with anticipation of what’s to come.

NOVEMBER - DECEMBER

With the first rain you start to understand how different a mediterranean climate garden is than that of a cold climate - it almost feels like a different hemisphere. Summer in a cold climate is the time of exuberant growth, with towering perennials and great plumes of ornamental grasses. Summer in a dry mediterranean climate is the opposite, a time of complete dryness and dormancy. Late fall/early winter in the cold climate is when plants have mostly died back and are buckling down for a long winter dormancy, whereas this same period in the mediterranean climate is the beginning of the growing season - where the first rains in November bring about a fresh flush of growth from the long dormant plants and joyful bloom from various bulbs.

The garden should be filled with thousands of autumn-blooming Crocus sp. and Sternbergia lutea, to really explode once the first rains arrive. Within two weeks after the first rain the ground will be carpeted in color. Perennials will quickly show their first green leaves after the rain, but will take a bit more time before they are large enough to make an impact, so these bulbs are key to providing early interest in the garden.

I am experimenting with various Crocus to see what returns and blooms without winter chill. Crocus goulimyi is a stunningly translucent flower that is just incredible when backlit, and should reliably return and even naturalize in our climate. Unfortunately, it is only rarely available, so I am very slowly growing some, but it will take many years until I have a good stock. The commonly available Crocus sativus, the source of Saffron, is well-adapted to our climate, but is only a sporadic bloomer.

DECEMBER - FEBRUARY

By December, when the Crocus have finished blooming, the new green foliage of perennials and grasses is starting to feel more lush. Much of the bare space is starting to fill, but there are still empty spaces, eliciting the need for some flower display to make it feel more complete until things grow in. Anemone coronaria is another early blooming geophyte that can make a real show in this early period. The hybrids such as ‘Sylphide’ and ‘De Caen’ are widely available, but their ability to withstand the aridity of Los Angeles is yet to prove itself in my garden over the next year. The species itself, native from Greece to Syria and down to Israel, should grow very well in Los Angeles without irrigation, but is not available from bulk bulb sellers.

FEBRUARY

February is the last month of ‘early Spring’ before flowers and plants really get going. Here we utilize two key species in relation to one another - swathes of yellow Tulipa sylvestris carpeting any remaining bare areas, and the mounding Cedros Island native Verbena lilacina ‘De La Mina’. These mix with the pink-lavender of Linanthus californicus, tucked away next to the Verbena, and the beautiful white flowers and see-through, ferny foliage of Astragalus trichopodus var. phoxus, a southern California native.

Tulipa sylvestris is a widely available species Tulip, native to the Mediterranean and naturalized through most of Europe, and handles our climate beautifully, emerging in January and going dormant in summer. While Tulips are generally thought of as maladapted to our mild climate, needing a winter chill, Tulipa sylvestris (as well as the also readily available Tulipa clusiana var chrysantha) can bloom and return with no need of chilling. Additional species from the eastern Mediterranean such as Tulipa agenensis sharonensis, native to coastal Israel and Lebanon, as well as Tulipa cypria, from Cyprus, are both adapted to arid coastal environments that do not experience frost and should do well in LA. I am slowly growing a handful of these from seed. Look up Tulipa cypria - it is breathtaking.

MARCH

March is Spring in full effect. All of the perennials are in full growth and you have your choice of thousands of perennials to choose from for floral combinations in this period. I think it’s fun to switch to a warm palette here from the cooler tones of February. The Verbena lilacina will keep blooming until it goes dormant, and it would clash with these hot tones, so I would suggest cutting it back a bit to slow it down and get rid of the flowers.

Penstemon eatonii and Baileya multiradiata do not seem to need water at all, and this makes sense with their desert upbringings. Yet using desert plants is not always so reliable; some of the Southwest deserts experience the tail end of summer monsoons coming up from Mexico, so even though the total annual rainfall is minimal, they still get rainfall on a more consistent basis than you get in the dry mediterranean-climate of LA. I’ve had a few desert plants die of drought in our summer dry period. That being said, these two plants have no problem here. Throw in the similarly hot coloring of Sparaxis tricolor, a South-African bulb, and you have a fiery planting matching the rising temperature of the season.

APRIL

Penstemon eatonii is almost too adapted to aridity - it will literally flower itself to death if you let it. For this reason, as well as in the favor of continuing to explore different color combinations across the season, I suggest cutting it back in April. Returning to a cool palette, Anagallis, Sisyrinchium, and the Chilean Leucocoryne create a mix of blues and lavenders, with highlights of red and yellows to recall the previous palette.

The Sisyrinchium comes to life right away after the rain but takes some time getting to flowering size. In April it is finally ready to bloom, but it will go dormant soon after. It can be planted at the base of later blooming perennials such as Monardella sp., Eriogonum grande var. rubescens, and Zauschneria. The flowers will rise through the foliage of these plants while they are still emerging, and then when the Sisyrinchium starts to go dormant, the dying leaves will be hidden by the host plant’s flowers. Many annuals can be treated the same way, especially those with cauline instead of or in addition to basal foliage, such as Papaver heterophyllum. The plant will grow while the nearby perennial is still emerging, it’s flowers blooming above the fully-grown foliage, and then it can be left to go to seed, hidden in the foliage and flowers of the perennial.

MAY

May is a turning point in the dry garden. The frequency of rain has dwindled, if not stopped completely, and plants start to show signs of real drought stress. The plantings shift from an overall feeling of green to one of gold and brown. There will still be blooms through the summer, but the overall feeling is significantly different. In May, the slowly rising foliage of Nepeta tuberosa has reached it’s zenith, and the terminal flowers spikes open to a deep purple. Stanleya pinnata, with a similar spire-like form, serves as a interesting foil for the Nepeta, and vice versa. These play off nicely against the golden hues of Festuca californica, Aristida purpurea, and Stipa speciosa.

JUNE - JULY

June and July is a study in reds, yellows, golds and browns. As a sort of last hurrah, Delphinium cardinale seems to burst into flower just as the dryness of summer really sets in, with stalks of cardinal-red blooms reaching up to seven feet tall. This is offset by lower but similarly vivacious blooms of Eriogonum grande var. rubescens and the final bulb of the season, Allium sphaerocephalon.

AUGUST - OCTOBER

From August through October, you wouldn’t expect much in the way of flowers. Zauschneria canum defies all expectations, in full neon orange bloom from August until October. This is accented by the browning seedheads of Eriogonum grande var. rubescens, and the golden dormant grasses. There are other bulbs and flowers that bloom in the driest parts of summer - Calostemma purpureum and Amaryllis belladona for instance - but nothing quite matches the ease and brilliance of Zauschneria. Even when cutting back the garden in October, it seems it could go on blooming.

Conclusion

Planning a garden in a dry summer climate, like any climate that deals with dormancy, requires careful planning and forethought. But in this process one becomes intimately aware of local climate and by extension, the natural world. A garden tied to climate ties you to place, and makes you, as garden-maker, part of the natural world rather than separate from it.

We don’t know what the future holds for the climate of Los Angeles. If you subscribe to the latitudinal shift forecast of climate change, the city will become more and more desert-like in the near future. Yet we’ve barely scratched the surface of the potential of climate-based gardening in Southern California. Celebrating dormancy, seasonal change, and aridity with perennial planting design enables us to be more in tune with our current climate, and can better prepare us for a future where we are forced to adapt to a new one.

© All Rights Reserved, Jonathan Froines