Bulletin of the American Rock Garden Society Volume 52 Number 2 Spring 1994 Cover: Primula angustifolia, Rhodiola rosea, with Pardosa sp. by Cindy Nelson-Nold of Lakewood, Colorado All Material Copyright © 1994 North American Rock Garden Society Bulletin of the American Rock Garden Society Volume 52 Number 2 Spring 1994 Features Troughs: A Special Love Affair, by Given Kelaidis 83 Plants for Troughs, by Geoffrey Charlesworth 89 Trough Construction, by Michael Slater 101 Soils for Troughs and Other Containers, by Jim Borland 113 Care of Troughs, by Anita Kistler 125 Tips on Troughs, by Rex Murfitt 127 Departments People 132 Gardens 133 Propagation 134 Errata 137 Plant Portrait 145 Books 146 82 Bulletin of the American Rock Garden Society Vol. 52:2 Troughs: A Special Love Affair by Gwen Kelaidis _ Iam that variety of gardener who turned right side up. Thankfully, Stan gardened although I lived in rented offered to construct troughs for me, apartments, tilling first one yard, then provided only that I would plant another. In 1975 I inherited two them for display at the 1986 Interim troughs from my friend Jim Sawyer International Rock Garden Plant and planted them to sempervivums Conference in Boulder, Colorado. So and sed urns. They sat on either side of began an extra-garden affair that has the sidewalk leading to the front door, continued to this day. taking the humble place of sentinel lions and eliciting many questions A trough is a garden unto itself, a from passers-by. And when I moved landscape and plant community com• to Colorado, they moved with me. plete on its own. The container frames So began my adventures with and gives this landscape shape. Rocks troughs, but it wasn't until 1985 that I and soil can be selected to suit the became a real devotee.Our friend needs of the plants and can easily dif• Stan Metsker suggested pointedly fer from those of the larger garden. that I plant anything important to me The trough can be designed to repre• in troughs until we found a way to sent a little slice of a natural ecosys• buy a house. It made sense, yet I had a tem, or it may simply be a container large appetite for plants and would with plants of similar stature and eco• need many troughs. logical needs, such as cactuses, or kab• I had tried my hand at making schia saxifrages. If I really want to troughs in molds, and it was the grow a plant and can't meet the soil unmolding process that was the prob• requirements in the garden, I dedicate lem. I have trouble even removing a trough to it, as I've done with Gen• jello from its container. I tried the tiana verna (needing peaty soil) and free-form trough, building upside• Petrophytum caespitosum (requiring a down in wet sand.Lumpy bowls with tight, dry crevice). thick rims resulted, their shaved off There are three compelling reasons bottoms usually not in quite the prop• to place a plant in a trough rather er plane to have them sit flat when than in the open garden. 83 Plants Don't Get Lost with the drier environment of the Some plants are so small that they trough.All of my garden soilscontain get lost in a rock garden. Examples a large component of clay loam. In include the tiny dryland Penstemon this climate with 12" tol5" of rain, pumilus, choice Talinum species, such some clay is advantageous, giving the as T. sedoides (T. okanoganense), T. brev• soil the ability to hold some moisture ifoiium, and T. pulchellum.Lesquerella longer. However, in wet spells when alpina and Penstemon acaulis are we receiveafternoon thundershowers almost that small, growing to an inch everyday for a week or two, plants in or two in diameter in some years. the garden may get too wet. In winter, Other very slow growers include also, in the cold north shade of ever• Lepidium nanum and Kelseya uniflora. green trees-where there is no shade In the garden such plants are easily in summer because of the higher overgrown by larger neighbors. They angle of the sun-even acantholimons also have little visual impact even in seem to suffer. In the troughs it just bloom, unless planted in groups of seems that the soil stays drier. five or more. Wouldn't we be lucky to have a dozen or two with which to Freedom of Design experiment! In the meantime, I place That great old adage of rock gar• them in troughs, where they are pro• dening, "Use only one kind of rock," portionately important and where I can be Sidesteppedby the simple use can keep an eye on them. of troughs.My 1986 Conference troughs were a discovery ground for Plants Live Longer, Bloom Better me, a wonderful field of experimenta• In the last eight years of growing tion.I used many differentrock types, dryland plants of western North from rounded sandstone boulders, to America I have found that many sim• gnarled limestone,to slate, to the peb• ply survive only in troughs and not in bles of desert pavement, each in a dif• the garden. Penstemons like P. acaulis, ferent trough. I had the opportunity P. laricifolius, P. angustifolius, P. humilis, to build with all these different rocks P. caryi are stillbloomingevery year in on a scale without back strain, front• troughs, while their seedpot mates end loaders, or a large budget. In far• have long ago died in the garden. flung places of the West I picked up Astragalus spatulatus and species of rocks that I thought would look Toumsendia, such as T. hookeri and T. attractive in a trough, along with alpigena, have long lives in these ele• smaller rocks and a variety of pebble vated homes. The ball cactuses, of sizes for mulch. The plastic bags of which I am increasingly fond pebbles have been hard to keep track (Echinocereus, Coryphantha, Mammilar• of in the potting shed (oncea garage). ia, Pediocactus, Sclerocactus) seem to I have developed a system of sorts, winter very well in troughs. Cactuses, keeping extra rocks and pebbles for especially opuntias, can change the each trough in a gallon-sizeor larger design feelof a garden, but in a trough pot, and the matching gravel inside in they can have a world of their own. a plastic bag. Eventually the mulch Cactuses often self-sow, and seem needs to be topped up, what with happy with companions such as those watering, replanting and, in my case, mentionedearlier in this paragraph. toddlers. It helps to hold your hand I can only speculate that this longer over the mulch while watering, so life for plants of the West has to do that no gravel washes off.When there 84 Bulletinof the American RockGarden SocietyVol.52:2 is simply no longer enough mulch, they are fairly large solid particles, you are forced to return to the original and inside them there is no room for location for more gravel-usually a air and water. If a rock half as big as a great pleasure. pot is added to the soil of a container A favori te theme for design in a and the formula recalculated, the air trough is to recreate a natural plant space will be considerably reduced, association. I try to achieve something of but the plant roots, since they don't the feel of the landscape, using the pri• grow inside the rock, will not experi• mary or dominant plant types from the ence a decrease in available air. What area. My Pikes Peak trough, then, had to has really changed for the plant is the include the famous Telesonix iamesii. the inside shape of the pot. Similarly, large bright blue bells of Mertensia alpina, and gravel in a mix doesn't impact the air still it is not really complete without space available to roots as much as the Eritrichium nanum, Primula angustifolia, formulas imply but rather creates a and Androsace chamaejasme. I have a convoluted soil shape within the con• trough from central Wyoming with tainer.Also, water moves more quick• dwarf sagebrush (Artemisia arbuscula), ly through the pot along rock or grav• Castilleja, and a dainty Erigeron. I should el surfaces than it would through, say, add an Astragalus or two and the small a clay. The current formula neglects creamy beauty Physaria eburnijlora. The the factor of time. How long it takes Laramie Plains trough has a glorious for the air spaces to be cleared of specimen of Astragalus spaiulatus, along water matters. with Toumsendia exscapa, a penstemon or My peat trough has mostly peat two, Se/aginella densa making a low, and a little sand; the alpine troughs olive green patch of turf, and Eriogonum have some sand, some gravel, some flavum. This trough I consider a great clay loam, a little peat, and perhaps a success, as plants are now self-sowing. I little Turface; the dryland troughs should mention that it is wonderful to have less gravel, usually no peat, per• have several plants of each species in the haps more Turface. Turface is a baked trough, echoing each other whether in clay product a bit like kitty litter, but bloom or out and giving the trough a baked harder, so that it doesn't break sort of unity that a group of solitary down. It makes the soil fluffier, and beauties cannot achieve. Because of my the only problem I have with it is that interest in producing seeds, I prefer at soil mixes with a high percentage of least five plants of a kind in each trough.