To understand the unique role of terra cotta pottery in the American west we must first look back to the gardens of Persia. There, and in the deserts of Africa the homes were turned inward with doors and windows opening onto a central courtyard. The days were spent within these enclosures protected from hot winds and shaded by the building walls.
In this arid climate, each drop of water was precious. The people found that growing plants in pots insured water was applied directly to the plant’s root zone, instead of disappearing into the thirsty desert sand. This same gardening technique came to the new world with the Spanish settling first in Mexico, then moving northward into what is now the southwestern United States. In these dry climates, before the advent of irrigation and pressure systems, watering many small pots was the easiest form of gardening.
Terra cotta clay pots are widely available in a huge assortment of sizes, shapes and styles. Urns, bowls, boxes, cylinders, window boxes, and traditional flower pots each offer a unique character. The earliest pots were water jars, tall and gracefully proportioned. Similar jars today may even be used without plants, or filled with the simple lines of leafless willow whips or bamboo poles.
You will find there are considerable differences in price for what appears to be the same pot. This is because most terra cotta pots are usually Italian or Mexican in origin. The Italian terra cotta is more expensive, but of better quality. Their are fired at higher temperatures and resist water absorption, which makes them better for cold winter climates. Their surfaces tend to be much smoother as well. Embellishments or patterns on these pots are well defined and crisp with more classical shapes.
Mexican pots come from small villages with no standardization as to clay type or firing, and as a result, the surfaces will have a rougher texture, thicker walls, and fuzzy detailing. Mexican pots are far less expensive because they are made at our doorstep, while heavy Italian products must be shipped across the Atlantic.
Mary Ensey is sales and estimator for an American clay products company, Gladding, McBean in Lincoln, California. The company was founded in l875 and specializes in custom architectural terra cotta made from local Sierra Nevada Mountain clay deposits. “People who live in very cold climates should choose their pottery with care. Clay pots exposed to repeated freezes and thaws must be very dense and fired at extremely high temperatures. If under fired, the clay will turn to shale and simply break apart as water absorbed into the clay expands when frozen. To test the quality of a pot, scrape the surface with a knife. If the clay comes off it is probably underfired and won’t last. If the surface remains intact, it is a quality product.”
Terra cotta is a natural colored clay which is easily worked by hand without special machinery. But Mary tells us “the exact coloring of the clay varies from place to place. Our clay tends to be more beige than red, although we do have to match terra cotta coloring for our architectural jobs.” The warm rusty coloring of typical terra cotta greatly enhances the green foliage of plants. Typical flower pots are porous, and the ready exchange of air helps to prevent saturation of plant roots as occurs frequently in plastic pots. Glazed or thickly painted clay pots lose this ability to exchange air through the walls.
There are also disadvantages to using terra cotta. Pots of any size are extremely heavy and difficult to move, which is a big problem where plants must be moved around or sheltered for the winter. Clay pots are also breakable, and with the prices of larger containers being quite high, the risk may be costly. Perhaps the biggest complaint is that pots eventually discolor, or develop a white mineral crust on the outside as water evaporates, leaving behind its salts. Regular scrubbing may help to discourage mineral buildup.
Fortunately there are now a few companies making a good replica of terra cotta pots that fool even a trained eye, but there are still questions about their ability to withstand extreme cold. They are constructed out of heavy molded plastic and accepted by most architects. Although as expensive as the clay pots, these are very strong, light weight, unbreakable, and do not have problems with discoloration. The popularity of these replicas is growing because of the ability to retain soil moisture longer and eliminate evaporation through the pot.
Beware of thinner, cheap plastic pots colored to look like terra cotta. These do not have the ability to withstand prolonged exposure to sunlight which gradually breaks down components in lower quality plastic. Definitely not worth buying at any price for they eventually become brittle and break apart.
Terra cotta pots are an important part of the southwestern look. They are set upon patios, along walkways or on top of thick walls. We always think of flowering annuals for pots, but planting them with permanent leafy greens, cacti, and flowering vines gives us interest year around.
The timelessness of terra cotta pottery is well known at Gladding, McBean. “We are still making the same pots as were illustrated in our 1936 catalog.” Mary tells us. “There has been no need to develop new designs because the classics never go out of style.”
In old Spanish and Italian gardens, the winters were often too cold for citrus. To solve the problem gardeners grew these evergreens in large terra cotta pots. In a special open space in the garden they were arranged in a grid, much like an orchard of potted trees. In the fall the pots were moved indoors or under the eaves of the house to protect them from frost. We too can learn from these old gardens and our pots may have small trees as well. Plants grown as “patio trees” such as white oleanders, Raphiolepis ‘Magestic Beauty’, azaleas, tree roses and many others are perfect choices. Since they require a large pot, you can plant annual color around the base of each patio tree, or use a permanent dwarf ivy or vinca groundcover to hang gracefully over the edges.
The most important factor in growing any potted plant is drainage. The container must have a drain hole in the bottom. It is advisable to have a catch basin beneath the pot because the water draining out the bottom may stain paving or rot wood decking. However, if there is standing water in the basin in between waterings it will prevent the pot from draining properly and the saturated soil rots the roots. Dump the basin if necessary or cut back on watering. To help the drain hole work better, line the bottom of the pot with shards of broken pots or a layer of gravel before filling the pot with soil mix.
It’s not a good idea to use natural soil to fill your pots. Buy commercial potting soil in bags as it contains lots of light woody material that helps reduce compaction and keeps the soil opened up enough to insure fast drainage. For cacti and succulents the soil mix must be even lighter and very fast to drain. How fast? Water should drain through within 15 seconds after filling the pot.
One of the big mistakes by inexperienced gardeners is putting too much soil in the pot. The idea is to have the soil line low enough so you can fill the pot with water once, then and let it seep in at its own rate. A overloaded pot cannot hold much water, and you’ll have to fill it a number of times to completely moisten the soil. For smaller pots the soil line should be at least 1″ below the rim, while larger containers need from 2 to 3″ or more depending on size.
Plants growing in pots quickly consume the soil nutrients for they cannot reach beyond their limited rooting zone. To keep them in top form its important to fertilize on a regular basis so the nutrients are constant. During peak growing periods every 2 or 3 weeks is average. The best types of fertilizers for pots are mixed with water and poured into the pot. Either a concentrate or soluble crystals such as Miracle Grow are perfect. Be sure to water generously for a few days after fertilizing so there is no risk of burning.
Ways to Water
Plants grown in pots must be watered frequently and well enough to wet the entire root zone. It helps to buy a watering wand attachment for the end of the hose because the nozzle at the end acts much like a shower head to distribute the flow over a larger area. Newly planted annuals can easily be disturbed by forceful water and soil is lost as well.
The main reason why we see so many potted plants today is because of easily installed drip systems. These low pressure spaghetti tube systems are sold at all home improvement stores and are simple to make with a pair of scissors. You can tap into a sprinkler riser or a hose bib, and water all the pots at once. When attached to an automatically controlled sprinkler system, the pots will be watered at the same time as the rest of your landscape. For larger pots with more demanding trees and shrubs, look for the perforated rings of tubing which distribute water over a larger area.
You can use more than just colorful bedding plants to capture the flavor of the old west. But exposure is the most important factor in plant selection, for with too much or too little sun your plants may not thrive.
- Desert Plants
Cacti and succulents are the most traditional southwestern plants and guarantee diversity of form and color. Cacti have common names which refer to their shapes, such as round barrel cactus, tall organ pipe, and beaver tail opuntia. Ice plant represents the succulents and cascades beautifully off the edges of taller pots. Even the euphorbia, crown-of-thorns with its coral red flowers and strange snaking form is a great choice.
- Bedding Plants
Annual bedding plants can be mixed and matched to provide instant color. Remember to place the taller growing varieties toward the center of the pot. The shorter plants next to these and cascading ones around the outside so they can grow to hang over the sides of the pot. Annuals combined with perennials makes sure the pot is still attractive during the off season, or if you are too busy to plant flowers.
- Long Lived Perennials
Perennials mean you plant the pot just once, rather than seasonally with annuals. Geraniums are one of the most popular plants in Mexican gardens for their care free manner, and their effect is enhanced by combining the fuzzy, upright zonals with cascading ivy geraniums. Sword ferns, asparagus ferns and impatiens are perfect for shadier locations.
- Reed-like Plants
Easy to grow lily of the Nile and other plants with reed-like foliage are especially attractive in square pots or urns. Sanseviaria, the mother-in-law’s tongue is exceptional in terra cotta window boxes. Bronze or variegated New Zealand flax are forgiving and grow quite large with their unusual coloring blending nicely with the red clay.
- Vines and Groundcover Plants
Plants that climb or cascade make the most out of pots. Vine runners may snake up walls or columns to spread out and bloom. Dwarf bougainvillea becomes a haze of electric color which is easily moved indoors for winter. Even roses take well to containers. Groundcovers spill out over the edges of your pots with dwarf variegated ivies and periwinkle (Vinca minor) the star performers.
Terra cotta pots with their timeless beauty are the key to the western garden character. You’ll find a limited selection of inexpensive clay pots at most home improvement stores. More sophisticated shapes and styles may be sold at your local garden center, but if not in stock they will have access to companies that specialize in Mexican or European red clay products. Whether hanging or standing, alone or in a creative grouping, even apartment dwellers may grow terra cotta gardens and share in the earthy mystique of the American southwest.