Container Gardening With Natives
Native plants are indispensable landscape elements for Central California, fitting perfectly with our Mediterranean climate. Colorful, fragrant, and interesting, they have long filled a variety of roles in our gardens while requiring little care. It is surprising to note that they are rarely used in container situations. For those interested in bringing fragrances, colors, and a variety of foliage colors and shapes onto their deck or patio or to add a different element to their garden, here are a few tips to assist you in growing natives in containers.
CONTAINERS
When selecting the container size, allow room. for at least the following season or two seasons growth. A plant in a one gallon pot can be planted into a two gallon which would be adequate for one season’s growth. A five gallon would allow for a couple of seasons growth before any repotting would be necessary. Don’t overdo it however! Especially with native plants. When placed in too large of a container, the soil can stay too moist thereby fostering root rot. Some plants such as Cacti, Dudleya, most annuals and some perennials rarely need to be planted in containers beyond the five gallon size. Dudleya and cactus will actually do better in wider but shallower containers, Avoid black or dark green plastic containers, period!! These colors will absorb the Sun’s infrared rays (heat) and will bake or steam the plant’s feeder roots.
While lighter colored, non-porous plastics do have some advantages (light weight and durability), any discussion concerning plastic versus terra cotta, wood, or formed concrete containers hinges upon economics. Plastic containers a markedly cheaper, but earthenware containers offer a wide variety of styles and lend themselves to a greater diversity of garden themes more easily matching or contrasting existing material already in the garden or patio. Functionally, however, there isn’t much difference between plastic and terracotta or earthenware containers. If you are going to use terracotta or earthenware containers, make sure they are completely unglazed and the inside is unsealed. Plant roots and the surrounding soil needs to breathe. New terracotta pots should be soaked overnight in. water to rehydrate them and leach any chemicals from their walls. Also be sure to soak any used clay pots in a ten-to-one solution of water and bleach to kill any possible root rot organisms before reuse. A one hour soak is sufficient followed by another one hour soak in plain water to remove any chlorine residue.
WATERING
Plants in pots need special care when watering. These plants are not in the ground where their roots can find extra water when needed. Instead they live in a very porous material which helps prevent disease but has no flexibility if not watered as required or you leave on a weeks vacation during a hot, dry spell. If planning a short trip, set the container(s) in a saucer or tray with about an inch or so of water just before leaving. This water will be wicked up by the dry soil within the container to help the plant through the hot and dry times until you return. Placing the plants in part shade will also lessen water use. When you return, remember to remove the saucer or tray.
In the cool season, most plants will do quite well if watered only once a week. During their growing period and hot summer months, watering may need to be as frequent as three times a week. Water exits a plant through it’s foliage; it is the often amount of leaf surface that a plant supports that dictates it’s watering needs rather than what species it is.
Moving stressed plants to a shadier location will also reduce the amount of water loss through the heated leaf surfaces. Water during the cool morning hours, the earlier the better. This will discourage fungal related diseases which usually thrive in moist and warm conditions. If you go out in the afternoon and your plant(s) look water stressed, don’t water!! Move it/them to a shadier location and water well (several times) the following morning.
FEEDING/SOIL MIXTURE
Since these plants are in containers that don’t allow the roots to go in search of nutrients, you need to fulfill their dietary requirements. Most of the potting soils available are very nutrient deficient and may consist mainly of inorganic materials. These soils need to be supplemented with compost at a 50/50 ratio. During the growing season, the plant will need additional feeding. This can be accomplished by removing the upper one to two inches of soil from the pot and replacing with fresh compost. How much soil you remove depends on the height of the pot. As a rule of thumb, remove about 20 percent of the container’s volume. If you don’t have access to compost, use a slow-release commercial fertilizer that is balanced, such as 10-10-10 or 4-8-6. What you don’t want to do is feed the plant too much nitrogen. This will result in a lot of foliage but not the root system to support the water needs.
PRUNING
Generally pruning is done well after the plant has flowered or during the winter dormant stage to shape the plant. Removal of spent flower-heads may stimulate repeated flowering. Pruning can also be done for appearance alone. When dealing with shrubs and woody perennials, tipping back the spring growth is important. This often promotes a tighter, more compact plant with flowers closer together. Use sharp, clean hand pruners. Between pruning different plants, dip the pruners in a 15% bleach solution to help prevent the spread of disease (bacterial and viral). After pruning is completed, wash the pruners in plain water to remove the chlorine and re-oil and wipe with an oily rag. This prevents the chlorine from eating the steel.
PLANT COMBINATIONS
Just as in normal garden situations, compatabile plants placed in the same container or in individual containers situated together can often serve to enhance each other’s color, texture, and fragrances. There are many possibilities to explore.
FAVORITES LIST
The following plants are just a few that will do well in container situations:
Shrubs: California Bush Anenome (Carpenteria californica), Island Bush Snapdragon (Galvezia speciosa), Evergreen Currant (Ribes malvaceum), California Rose (Rosa californica), and various Sage species.
Bulbs: Onion species (Allium), Blue Dicks (Dichelostemma capitatum), and Brodiaea species.
Herbaceous Perennials: Yarrow, Maidenhair Fern, California Columbine, Coastal Sage Bush (Artemisia calfornica), Sulphur Buckwheat (Eriogonum umbellatum), Coral Bells, Sage species, Blue-eyed Grass (Sisyrinchium bellum), and Woodfern (Woodwardia fimbriata).
Succulents: Dudleya species do very well in container situations.
Annuals: Elegant Clarkia (Clarkia unguiculata), California Poppy, Baby Blue-eyes (Nemophila menziesii) and Bird’s-eye Gilia (Gilia capitata).
