I have a a very large planter that leads up to my front door which faces east. It’s 4ft wide, 7ft long, 4ft deep about 1/3 of it is under an overhang of the roof. So part of the flower bed is shaded and part gets the afternoon sun. I’ve planted annuals in it for the last few years but would like to switch to flowering perennials. I’d like something that flowers profusely and maybe some hostas(?) to fill in the gaps but I’m stumped as to what to plant. Please can you help!? Thank you.
Growing perennials in containers has become a very popular trend. Before choosing your perennials there are a few important factors to consider. The following information is from a number of our archived posts:
Overwintering perennials in containers is one of the biggest challenges faced by container gardeners in our zone. The freeze-thaw cycle is the main problem: that is, the melting of the water in the container’s soil during sunny or warmer spells, followed by freezing when the temperatures dip again. This is what kills a plant’s roots over the winter. Your most important starting point is the container itself: it should be as large as possible (the more soil it can contain, the more insulation it will provide.” Ensure that the containers are freeze-thaw resistant. Ceramic and clay pots will probably crack as will cheaper plastic pots. During winter months, shrubs often suffer from moisture loss (dessication) if they can not pick up enough moisture, especially before dormancy and freeze. Wind protection will also help minimize moisture loss.
For your container you may wish to consider a mixture of evergreens and perennials. Most perennials do not flower for the entire season. Incorporating perennials with height variation, which flower at various times and have interesting foliage along with some evergreens will keep the container interesting throughout the year.
The following information from another archived posts on the best evergreens for containers might be of use:
The best trees for containers are small and slow growing with compact root systems. Evergreens that are cold hardy in Toronto will need to be rated at zones 3 or 4 when in a container. Dwarf cypress appears to be a questionable survivor in our climate, however, Chamaecyparis or False Cypress would be a suitable choice and hardy to zones 4 and 5 and there is a great variety of colour, foliage and form available. Because evergreens transpire throughout the winter, they must be kept watered right up until the soil ball freezes hard. Spread out the roots at potting up for all plants. This article gives additional information.
If you want to incorporate a vine for height in your container a small clematis placed in the center of the container on a small obselik might be the answer. Any of the Raymond Evison clematis are perfect for containers. Daylilies come in a variety of heights, sizes and flower colour. Daylilies will flower in full sun- part shade.
The use of a grass like golden variegated Japanese Forest Grass can offer a fine flowing texture with colour interest as well. Japanese Forest Grass (Hakonechloa) comes in a variety of foliage colour form ‘golden variegated’ to ‘all gold’. This plant can grow in full sun, part shade and full shade. It has a beautiful cascading growth habit.
Some other ideas you might want to consider include the use of ground covers which can cascade or flow over the edges of your containers. Creeping Jenny (Lysimachia) comes in a lime green or medium green and has a yellow flower. Lamium can also provide a nice variegated cascade affect with either purple or pink flowers. Both of these grow in part shade-full sun. Some of the Sedums can cascade as well. Have a look at yellow-flowered Sedum sexangulare, or even hens and chicks (Sempervivum spp. and cvs.) for the sunny side of your planter.
Once your container is planted Garden making has an excellent article on How to Overwinter Perennials in Pots.