“Praise a large domain, cultivate a small estate,” wrote Virgil. Woody shrubs, grasses, perennials, groundcovers: practically anything that can be planted in the garden can fill your fall containers.

Design Considerations: We hardly need to worry about too much sun during our Northwest winters, but you should still consider the light and exposure your containers will get and choose plants accordingly. Choose plants that work well with the color of your home. Most should be “evergreen;” that is, plants that have leaves all winter regardless of their color.

Fall/winter container plantings grow very little, so think big. Choose plants large enough (4-inch and gallon size plants and larger) and plant the containers fully enough to make them look “grown in,” i. e., the way your summer containers look by the end of the summer.

Plant Selection: When planting your containers, it’s not the “paint” that matters; it’s the “painter.” While keeping your planting conditions in mind, how you use the plants matters more than what plants you choose. Create contrast, movement and interest in your containers with whatever plants you select.

Bulbs/Annuals: We have limited choices for winter annuals in our Pacific Northwest climate—pansies in the fall and primroses in the late winter—so consider a strong mix of foliage plants with a lighter mix of flowers. Tuck a few bulbs in your containers as well as annual flowers.

Foliage Effects: Evergreen grasses, like Carex dipsacea (Autumn Sedge) and Carex flagillifera (Brown Sedge) take on golden brown colors in the winter. Variegated grasses like Acorus gramineus ‘Ogon,’ with its yellow variegation, and Acorus gramineus ‘Variegatus,’ featuring a cream/green mix, brighten shady pots. Blue grasses (Festuca glauca ‘Elijah Blue’), dark red grasses (Ucinia uciniata), and even black grasses (Ophiopogon planiscapus ‘Nigrescens) appear at reputable nurseries.

Contrast these fine-textured plants with bold plants like the many types of Heuchera (Coral Bells) now available in the trade. A study in contrasts, Heuchera ‘Marmalade’ is a beautiful warm butterscotch color while Heuchera ‘Obsidian’ is a rich black/brown. Bergenia (Elephant Ear), another big leaved perennial, can take on reddish tints in cold weather and blooms on a tall spike in late winter/early spring.

Euphorbias are often are sold as 4-inch or gallon plants in the fall as are new species of Hebe. Euphorbias are a medium-textured plant and include upright and trailing forms. Hebe has leaves similar to boxwood and comes in purple, variegated and blue-leaved forms. These medium-textured perennials and shrubs make wonderful foils for both fine-textured and broad-leaved plants.

Conifers and shrubby evergreens, like the winter-blooming Camellia sasanqua, often appear in gallon sizes in the fall and transplant easily to the garden later.

Groundcovers like the new cultivars of Ajuga reptans (Bugleweed) can be used as filler between other plants. Vinca major ‘Wojo’s Gem’ is a variegated trailing vinca and a great substitute for ivy. Your fall/winter containers can be as glorious as any planter full of spring flowers!

The Final Step:  Container Maintenance

Container plants are like your children:  don’t go to the trouble to create them and then never wipe their noses or comb their hair.   The most wonderful design and installation in the world will quickly go to “pot” (ahem), if the maintenance is neglected. Containers are the highest maintenance elements in a garden because of the need for fairly regular watering, feeding and grooming. From highest to lowest, the order of maintenance needs for plants in a container is annuals, perennials, shrubs, and trees. Annuals should be deadheaded and yellow leaves picked off once a week at least, whereas shrubs and trees may need to only be pruned every two or three years (although they make up for the lack of regular maintenance when they have to be repotted). 

WATERING: The “finger test” is critical for monitoring your containers. Stick a finger in the soil of your container in at least three places to the depth of your finger. If moist soil clings to your finger when you withdraw it, you don’t need to add water to that container. Once you become experienced at observing your containers, you may not even need to do that—but it is foolproof. Don’t time your watering on some pre-set schedule. Here in the Pacific Northwest in the early spring, we may not need to water our containers initially for quite a long time. The best way to water a container is by hand. However, a great deal of time can be saved by watering your containers automatically, either from a hose bib/clock system or by attaching them to a nearby landscape zone.

If you are watering containers by hand, be careful not to let them get completely dry. When we water a completely dry container “until the water runs out the hole at the bottom” we still may not be watering enough. Completely dry soil will not absorb the water at first. The water will simply “sheet” across the top of the container and run down between the soil (which has shrunken away from the pot) and the sides of the container, finally running out the bottom. Fill a dry container with water at least three times, then do the “finger test” again to see if the soil is wet.

The smaller the container, the more frequently you will need to water it. Suit the container to the vigor of the plants.

FERTILIZING: Because the roots of container plants have nowhere to go to get extra nutrition, it must be provided for them at the beginning of the installation and/or along the way. Seasonal Color Pots uses organic fertilizers and excellent potting soil to offset the need for too much later fertilization. Nevertheless, in the last two years we in the Pacific Northwest have experienced very cold, rainy springs. This washes so much nitrogen out of the soil that some extra fertilizing is needed. Fertilize as little as possible. All the fertilizer in the world will not make up for poor potting soil or poorly selected plants.

Never, ever fertilize your containers when they are dry. You will burn every plant in the pot.

DEADHEADING: Container plants will need to be deadheaded (the faded flowers picked off) in order to keep them blooming. If dead blossoms are left on the annuals, they will not be as floriferous as they could be. Use a scissor or pruner and be sure to deadhead the flowers back to the base of their stem. Do not leave unsightly dead stems sticking out of the plant. Any stems left on the plant sends a message to the annual that a flower still exists and it will put out fewer flowers as a result. Yellow or damaged leaves should also be removed. Do not try to pull off the faded blossoms without cutting: you will likely pull your plant out of the soil.

Adding slug and snail bait after watering will help fight those persistent Pacific Northwest pests.  I use an animal friendly slug bait like Sluggo or Worry Free.   

The same rules apply for any plant you use in a container, whether it is an herb and annual or a perennial, etc. It still needs to be groomed over the course of the growing season.

DESIGN WITH THE LIVING: PLANTS FOR CONTAINERS

PLANTS—What makes a good container planting? Contrast, form, focal points, color, line—all the same elements that make a good landscape planting. I strongly believe that when it comes to container design, it’s not the paint, it’s the painter. In other words, it matters less what kind of plants you use than how you use them.

• Choosing Plants:  Always take into consideration the conditions the plants require. Read your plant tags and talk to knowledgeable nursery people. The smaller nurseries are usually your best resources for this type of personnel. If they have a CPH (Certified Professional Horticulturalist) on staff then you can be pretty sure you are getting good information. For example, if a plant tag says Full Sun, that typically means hours of direct sunlight during the hottest part of the day (10 am to 2 pm). Direct sunlight from 3 pm to 6 pm is not the same. Part sun or Part Shade usually means morning sun, afternoon shade. Also, talking to good nursery people is even more helpful because they have experience with how the plants actually perform here in the Pacific Northwest, in addition to what it says on the tag, which can sometimes be somewhat generic.

• Mixed Containers:  If creating a mixed container, one thing to really take into consideration is contrast. If all the plants in the containers have the same texture—all fine leaved or all broad leaved—then the planting has no contrast. I like to be able to look at a container and have my eye “flow” around the container. I don’t like for a container to look “busy” to no purpose. Be aware, also, that you can try to put too many different kinds of plants in a mixed container—too much of a good thing, so to speak. I like to limit the different kinds of plants to 3 to 5, not including any centerpiece, if I have one, and then mass those chosen plants to fill the space.

Alternatively, if you have room for a container grouping with some smaller but wonderful containers you want to use, don’t try to create a mixed container. Use one beautiful plant in the container that will fill it and be in scale with the container.

Warm Weather Containers:  Warm weather containers planted with nothing but flowers really start to look shabby by the end of the season. Use foliage plants–hostas, coleus, ferns, and grasses–or woody plants to add drama and scale to a container. There are also dark leaved fuchsias like Gartenmeister that add foliage and flower interest with one plant. One of my favorite Pelargoniums (the annual geranium) is ‘Persian Queen’ which has chartreuse foliage and also a hot pink flower. There are now geraniums with variegated leaves—both white/green and orange/cream. I feel the same way about dahlias. Using a dark leaved dahlia gives you more “bang for the buck” because you get the interesting foliage and well as the flower. Foliage plants and structural plants add drama and sophistication to a container. Variegated foliage plants can also be wonderful, such as variegated vinca—-as opposed to ivy, which tends to become ubiquitous—–or one of the many beautiful variegated hostas. Grasses can add a wonderful sense of movement to a container. There are shade loving grasses like Luzula nivea, our native woodrush, which has white puffs of flowers even in the shade, or Hakenachloa macra ‘Aureola’( Japanese Forest Grass) which has chartreuse and slightly pink striped foliage and can create quite a mound. Certainly we have many, many sun loving grasses to choose from.

Cool Season Containers:  When the cool weather arrives, what flowers can we choose from here in the Pacific Northwest that will last all winter long in a container? Pansies. We can choose to use asters or a few other things that will last for a short while, but primarily pansies are our choice until annual primroses arrive in the nurseries in February. I do use florist’s cyclamen or Cyclamen persifolia in containers for a few folks who like it and can afford to replace it. Therefore, a cool season container based on flowers is going to be pretty dull. Contrasts in shape and texture via foliage plants are going to make a good cool season container.

Some of my favorite plants for cool season containers are evergreen, even if they aren’t green as such. Bergenia is a great broad-foliaged option. There’s one out there now that is variegated called Bergenia ‘Tubby Andrews’. Euphorbias like ‘Red Edge’ or ‘Red Martin’ will add stem color as well as foliage color and bloom for you in early spring or late winter. Grasses are always a good choice. We have a couple of new Liriopes—’Silver Dragon’ and ‘Silvery Sunproof’ which like the shade and are silver and cream striped, respectively. Phormiums, or New Zealand Flax, will cross over all the seasons as long as the winter is not severe. If you have the space, stuff bulbs under the planting and those will perk it up in the spring. Again, variegated evergreen plants are great for brightening up a winter container, as are silver foliaged plants like Senecio greyii or even Eucalyptus in a protected spot.

If planting shrubs and trees in a container, be prepared to change them out at some point if they show signs of stress; although the right woody plants can live for a long time in a container if it is large enough. Annuals grow very fast in one season, perennials less so, shrubs and trees not much at all. Plant for the future, whether that is the end of summer or five years from now.

June Posting: Container Maintenance