Planning Your Garden
Patio Gardens: Experimenting with Native Plants for Containers
Hummingbird Coyote Mint (Monardella macrantha), Covelle’s Lipfern (Cheilanthes covilleii), and Greensphere Manzanita (Arctostaphylos 'Greensphere')
People often ask 'what native plants will do well in containers?' This is also a hot topic for native plant listserves and newsletters. Many of us don't have a yard of our own and yet we also want to participate in this 'gardening with natives' movement which is sweeping the country – even if it means taking our gardens with us as we move from one place to the next. There are also plenty of folks who enjoy an arrangement of beautiful potted plants as a focal point in their native plant gardens.
Sometimes I respond to the question by saying 'see that's looking great at the nursery – where all the plants are in containers – some for a very long time.' Although true to a certain extent, some of those will look great for a year or so, and then quickly decline unless they are put in the ground, while others just refuse to flower or even mature until they have more room for their roots.
I've been experimenting with many different kinds of native plants in containers of all kinds for the past decade, and I've definitely grown attached to some more than others. Your chance of success with potted natives will increase greatly if you educate yourself about which plants to use and how to care for them. In general, the goal is to get the most foliage color, beautiful texture, or vibrant blooms for as long as possible. It's fairly simple to have beautiful color for a very short time during the bloom period of most any plant, but most plants then quickly decline or go dormant until the following year. A good example of these are the Calochortus – either the Globe Lanterns or the Mariposa Tulips. I haven't figured out how to get these to thrive when planted in the landscape, but they are fairly easy to grow in containers. The crucial piece is that they need to stay completely dry during the hot months. After their gorgeous blooms, the long leaves shrivel and disappear, and the pot should be moved out of view until they break dormancy the following year. So those pots have a very short shelf-life, but at least they provide a way to grow these stunning flowers in our gardens.
Mimulus hybrid 'trish' and Foothill Penstamon (penstemon heterophyllos)
Succulents as Container Plants
In general, succulent plants are great subjects for potting. They often have fairly simple and small root systems which can grow in relatively small amounts of soil that gets trapped in exposed rocks – simulating the environment of a pot. We have quite a few stunning succulents which work beautifully in pots. Amongst them are the Dudleyas, Lewisias, Agaves, Cacti and Sedums. Lewisias are certainly a favorite – especially Lewisia cotyledon – Cliffmaidens – with their endless color variations, fascinating leathery rosettes of leaves, and very long flowering season. The important thing to remember when growing these beauties is to change their soil and plant in a larger pot every two years or they will begin to decline. I have some older specimens which produce a solid spray of gorgeous flowers 16-18 inches across.
Other Container Favorites
One of my favorite less well-known plants to use in unusual, biomorphic shaped pots is Platanus maritima or Coastal Plantain. This common plant of moist coastal sand dunes does very well in large or small pots, with or without drainage. They grow slowly to overflow the pot with their fat, tightly held leaves and then produce interesting flower stalks and copious amounts of seed which will then propagate throughout all of your pots – given the right conditions. Another one which I really love to grow in fairly large pots is Hesperoyucca whipplei – Our Lord's Candle. After three to five years in a carefully-placed pot [their spiny leaves can be DEADLY sharp!], they produce a 6-7 foot-tall flower stalk which lasts for one to two months and then the whole plant dies. Be sure to collect and plant the seed in a pot with gravel and soil mixed, and keep it watered in a hot, sunny location.
Cusion Buckwheat (Eriogonum ovalifolium var. nivale)
Dudleyas and Sedums or Live-for-evers and Stonecrops are probably the most forgiving of all natives in containers. A real stunner is Dudleya pulverulenta or Chalk Dudleya which can get enormous – single rosettes can reach 20 inches across! Dudleya virens ssp. hassei or Hasse's Dudleya has beautiful glaucous leaves in rainbow hues and can fill a very large 20 gallon pot in just a year or two. I've been paying closer attention in recent years to flower color in Dudleyas too. Some of the Dudleya cymosas – Canyon Dudleyas – have bright red or orange-red flowers, while many Dudleyas have a rather dull yellow flower color.
Placing Your Containers
One of the most important considerations when choosing the right plant for a pot is the location. Most potted plants prefer a place where their roots can remain cool and moist, but where their leaves receive as much sun as possible. These are seemingly contradictory needs, but they can often be met - particularly at the entrance of a home – where the pot can be in the shade of a tree, shrub or building structure, and the leaves can receive both direct and indirect sunlight. In general, you want to give plants in pots a slightly more protected or cooler location than they would want if they were in the ground. For example, sticky monkeyflower in the wild would be growing in full sun to partial shade. If I were to grow it in a pot, I would definitely choose a partial shade location for the pot –a location somewhat shadier than I would plant it in the garden. I prefer to locate containers where people spend time on a daily basis and where water is easily accessible. But don't despair if you don't have a location like this. There is a plant or two for practically any conditions you can come up with, but take the time to study and figure out which ones will work for your particular location before spending money on plants.
Soil and Soil Amendments
Cushion Buckwheat (eriogonum ovalifolium var. nivale)
The soil medium is very important with Dudleyas and many other succulents – they need near-perfect drainage and fertile soil to thrive. I mix my own soils for my pots and for these plants. For most native plants in a 1 gal pot, I mix 1 cup of pumice – 1/8-3/8, 1 cup of red lava – 1/8-3/8, and fill w/ potting soil. For Dudleyas, I add 1 cup of felton or #2 sharp sand to the mix. I also add about a tsp of timed-release fertilizer [Osmocote works] to the 1 gal container. The fertilizer should be well mixed into the soil and then added again after the time period for which it is meant to work [mine is good for 4-6 months].
Best Container Types
What are the best pots to use? Practically anything which is durable, can hold soil and has drainage holes can be used to grow plants in. I've used antique trash cans, industrial ceramic drainage tiles, carved stone, galvanized sheet metal boxes, brick planters, rusted iron, cracked cast iron pots, old teapots which have rusted out, and all sorts of barrels to grow native plants in. An important consideration is how much room the roots of the plants you choose will need. I've had success growing even a mature Bigberry Manzanita in a very large pot [4 ft tall x 3 ft wide]. A rule of thumb is to plant something which will be happy for at least the next two or three years. Then you can transplant it to a larger pot, root-prune it and attempt to grow it in a dwarfed form, or plant it out in the garden. You will probably soon discover that some natives grow very slowly to maturity and others seem to mature overnight and then need a larger pot. I have grown to dislike low-fired pottery, as it tends to disintegrate after a year or two. Remember also that square containers hold 50% more soil than round containers of the same size. Many plants – particularly the succulents – do better with a thick layer of pebble or crushed rock as a mulch. This absorbs and holds heat and keeps their sensitive crowns dry.
I usually plant communities or groupings of plants rather than single species in a pot. Some of the successful containers are listed below, and many of them are pictured at my Flickr Gallery, Container Gardening with Native Plants: http://www.flickr.com/photos/eastbaywilds/sets/72157594276050096/
A 15 gallon, glazed ceramic pot with Blechnum spicant – Deer Fern, Asarum caudatum – Wild Ginger, Claytonia siberica – Spring Beauty, and Scutellaria antirrhinoides – Scullcap. This pot is in mostly shade and sits in a catch-basin to ensure constant moisture.
A 10 gallon, glazed ceramic cubic pot with Arctostaphylos 'Greensphere' – Greensphere Manzanita, Monardella macrantha 'Marian Sampson', and Cheilanthes covillei – Coville's Lipfern. This pot is in half-shade, half-sun and is mulched with medium and small river-worn stone.
A 10 gallon, glazed ceramic pot with Rubus parviflora – Thimbleberry, Satureja douglasii – Yerba Buena, and Hydrocotyle verticillata – Water Pennywort. This pot is in full sun where it gets plenty of water. The Pennywort turns a beautiful red color in winter and again in late spring, and the Thimbleberry only loses it's large, fuzzy, green leaves for a short time each winter – due to the constant moisture.
Cliff’s Maids (Lewisia cotyledon)
A 30 gallon antique trash can with Aesculus californica – California Buckeye, Mahonia aquifolium – Oregon Grape, Polypodium californica – California Polypody, and Satureja douglasii – Yerba Buena. This has done very well in a partial sun location with weekly irrigation for seven years now.
A 2.5 gallon glazed round pot with straight walls with Aspidotis californica, and Brodiaea elegans – Harvest Brodiaea. This pot is filled with a mix of potting soil and gravel which gives it excellent drainage, but placed where it receives water every other day in almost full sun. It has done very well for four years now.
A 30 gallon unglazed, aged cement container with Corylus cornuta var. californica – California Hazelnut, Polystichum dudleyana – Dudley's Swordfern, Claytonia siberica – Spring Beauty, Smilacina stellata – Starry False Solomon's Seal, and Satureja douglasii – Yerba Buena. It's mulched with river-worn cobbles and decomposed granite and was planted with a mossy log which has almost completely decomposed now. It is in total, bright shade and receives weekly irrigation. Every couple of years, the Hazelnut begins to look a bit piqued and I add humic acid to it and it quickly picks up again – producing an interesting show throughout every season. The Dudley's Swordfern is especially beautiful [and nearly impossible to find].
A 12 gallon Italian terracotta cubic pot with Dryopteris arguta – Coastal Woodfern, and Darmera peltata – Indian Rhubarb, and Polypodium californica 'Sarah Lyman' – Sarah Lyman Polypody. The Coastal Woodfern is the centerpiece of this very attractive pot, while the Indian Rhubarb and Polypody take turns during their opposing seasons. This pot receives irrigation every other day.
My best advice to you is to experiment with what you like, consider leaf colors and textures as well as flowers, figure out what is going to look great for the longest time each year, give the plants plenty of room to grow and fill their pots, locate your pots in as ideal a place as you can, and ENJOY your potted natives without fussing over them too much.
Contributed by Pete Veilleux, East Bay Wilds
Pete Veilleux left a 20 year career in social services and international development to pursue his love of gardening w/ native plants in 2001. Hes since begun East Bay Wilds - a design/install and maintainenance service and native plant nursery. Besides attending presentations and lectures, collaborating and sharing info with knowledgeable horticulturists, ecologists, and botanists, he received his education while exploring our wild places. His favorite places extend from the high sierra and Mount Diablo to the Oakland Hills and Big Sur. He considers his most important tool to be his camera - which he uses to study plants in their native habitat as well as in cultivated settings. When landscaping for others, his primary goal is to help people make the connection between their yards and the greater, wild world around us. He wants people to experience the beautiful harmony that he sees around him when exploring the woods, meadows and high rocky outcrops around the state. Pete would love to hear about your successes and failures growing California native plants in containers – you can e-mail Pete at peteeastbaywilds.com.