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Q: A couple years ago I bought a 5 foot staked cape cod honeysuckle, (orange trumpet clusters). It is in a 3 foot tall 18 inch wide plastic container on my balcony. I live in P.B. across from the bird sanctuary, southern exposure. It grew and developed into a lush fabulous dense plant, (about 15 feet tall)  finches would make their nests and breed in it. A little more than a year ago the leaves got yellow and dropped.

My friend who also supplies me with organic fertilizer said it is the water, he was having similar problems. He planted 6 tomato seeds for an experiment. 3 got tap water, the other 3 filtered water – tap water grew to 2 inches, a bit sad looking. The plants that got the filtered water grew to about 15 inches in the same time and looked great. So I flushed the honeysuckle with filtered water.Filtered water in, sucked out the run-off and discarded it, I did this for an entire day, and cut some of its bare branches back. It seemed for a while the problem was arrested, but the tree was just existing, not flourishing. By then it lost about 75% of its foliage. 3 month ago it started again, leaves turning yellow and dropping, it looks pathetic, but still produces flowers.  I have shed tears hugging  my honeysuckle and told her how sorry I was that I don’t know how to fix this.

Your experience and wisdom are my only hope.

Answer from Pat:

It is very sad to have a beloved plant die. Fortunately, your question gave me all the clues I need to tell you what’s wrong with the plant. In a nutshell, it is not adapted to growing in a container and it has wet feet, but clearing up these problems may not save the plant. So let’s survey the facts and then look at possible solutions.

First, common names are subject to much confusion and the one you cite is incorrect. There is no plant called Cape Cod Honeysuckle, though you are not alone in using this name; it’s even on the internet. If there were such a plant it would have to be a hardy honeysuckle shrub or vine, most likely Lonicera japonica ‘Halliana’, a fragrant, white-flowered, hardy and invasive climber. (The word “hardy” has nothing to do with whether a plant is “tough” or easy to grow. Hardy applied to a plant means it is capable of going through a cold winter without dying.) The true honeysuckles are Lonicera’s. Many are fragrant but none have orange flowers. (Lonicera ‘Dropmore’ has red flowers and the rest are white, yellow, or bi-color.) Thus I know the plant you have with orange flowers is Cape honeysuckle (Tecoma capensis) and it is a large shrub which can be grown as a climber. The words “Cape” in its common name and “capensis” in its botanical name derive from the Cape of Good Hope in South Africa, where this plant is native, not from Cape Cod. This plant could not survive a New England winter on Cape Cod.

The main problem you are having is not alkaline water, but the fact that you are trying to grow Cape honeysuckle (T. capensis) in a container and it is not adapted to growing in containers.  Also the fact that you said you sucked out the runoff and discarded it sounds as if you used a bulb baster and that you have a saucer under the plant that fills up with water. If the roots of this container-grown plant are allowed to sit in water, this is a condition called “wet feet” and will kill this plant. Few plants like wet feet but particularly this one which is very drought-resistant and likes to run dry. The problem of wet feet can kill many plants, for example, a potted geranium will die from wet feet quicker than from any other problem. This can be solved by filling the drainage saucer to the very top with gravel and setting the pot on top of the gravel. Water will then drain down into the gravel and not touch the roots of the plant.

So let’s look at the characteristics of this plant. Cape honeysuckle is a large rampant shrub that can grow 20 or 30 feet tall if not frequently hard pruned to keep it lower. Grown in the ground it is a tough, easy, plant that can take alkaline water, grows well in any kind of soil, and needs little irrigation.  It likes to put its roots deep into the ground and prefers deep but infrequent watering. In coastal zones it sometimes survives with no irrigation whatsoever.

Your plant grew well at first because its roots had not filled the container. Once the roots had filled the container the plant probably got root bound. The roots ate up all the soil and went round and round. Now when you watered, the hole in the bottom might have been clogged with roots and water might have sat in the bottom of the container, thus killing roots. Or alternatively, water might have by-passed the roots altogether and run straight down around them into the bottom of the container and the saucer beneath. Either of these conditions can cause all the leaves of a plant to go yellow and fall off as you describe. It continues to flower because it thinks it will die. I have seen plants such as a dwarf Meyer lemon growing in a half barrel with this problem. It often happens to Ficus benjamina grown in a pot as a house plant.

If you were able to take your plant out of the pot and put it in the ground, it might survive. Unfortunately, your only solution now is to empty it out and try something else. For a quick cover this year, try scarlet runner beans. They bring hummingbirds. For a permanent fix, plant a shrub or climber better adapted to growing in containers. Some bamboos grow well in containers, including golden goddess bamboo (Bambusa multiplex ‘Golden Goddess’) and golden bamboo (Phyllostachys aurea). I have had luck growing angel’s trumpet (Brugmansia) in containers. I like the one called ‘Charles Grimaldi’ best but there are others that work well in containers also. Once established they need almost daily water and frequent fertilizer and bloom in waves of bloom year round.  Heavenly bamboo (Nandina domestica) is another plant that can survive in a container for some years and dwarf citrus is an elegant possibility, especially kumquat, due to its small size and dense foliage.

Regarding alkaline water, softened household water is not good for any plant since it contains more salts than ordinary tap water and these build up in soil. Most potted plants do okay with ordinary cold tap water, however, as long as the water is allowed to drain out the bottom of the plant and flow away from the roots. Filtered water is probably better as long as the soft-water company has come out annually check and confirm it is relatively free from salts. (Companies don’t do this service regularly unless a customer asks for it.)

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2 Responses to “Container-grown Cape Honeysuckle with Wet Feet”

  1. Thankful Gardener February 22, 2010

    Dear Ms. Pat,

    Thank you sooooo much for your detailed and speedy response. I was hoping for a different answer, but my gut knew different.

    I know not all plants do well in containers. In the past I have taken smaller plants out of the pot, cut the root ball down and put it back in the same pot with fresh soil, which worked for a while.

    The scarlet runner beans look beautiful and grow fast, just what I need. But if I
    understand correctly it is an annual and is done in autumn. I need shade from
    august till april/may (position of the sun), everything inside my place is being bleached from the sun, fabrics, pictures etc. Eventually it needs to be 15 -18 feet tall to be effective.

    I need inexpensive, fast growing, and also wanted something for my little animal friends to munch or suck on. Am I asking for too much ? I believe the trumpet vine is a slow grower, and never seen a bamboo flower, and if they do are creatures attracted to it. Could I do bamboo and put a few scarlet runner beans in the same pot, or would that choke the bamboo? Can scarlet runner beans grow year round in this climate, meaning when the summer crop dies another could come up, even if it would not be as luscious?

    I saw your picture in the paper and knew right away you are one of the “Earth Mothers” on this planet. Thank you for this, we are in need of more who think and do like you. I also know you have a busy life and a gardeners work is never fully done. I don’t mean to be impertinent and take up too much of your time.

    With much appreciation and gratitude, sending love from my house to yours.

    Reply
    • It actually occurred to me to give you an option where you might grow something inexpensive in the existing pot to climb up the existing plants, that’s why I thought of the scarlet runner beans, but if there is no soil left in the pot that won’t work. Scarlet runner beans are a warm-season perennial, not an annual except where winters are cold, and here in our mild climate they should continue growing through winter. You can plant scarlet runners next month, in March. South facing under an overhang means shade in summer but sun in winter. Plant the seeds on the sunny side of the pot so they get the sun. By August when the sun reaches your house, the vines should already be providing shade. Why don’t you try it and see?

      I think the idea of planting a fast growing plant from seeds is the way to go and let the existing plant be the support for the climber. With that thought in mind, here is another one: perennial sweet pea (Lathyrus latifolius.) It is a strong grower to nine feet tall. You need to continue picking flowers to keep it blooming.

      Additionally, I have thought of some other tall plants that can be grown in containers: Yew pine (Podocarpus macrophyllus), blue potato plant (Solanum rantonnetii ‘Royal Robe’) and hop bush (Dodonnea viscosa). Be sure to place containers where sun will hit the plants all year.

      Bamboo doesn’t really bring birds, but it would be more likely to choke out the scarlet runner beans than vice versa and is not tall enough to do the job you need done.

      Another note: If the Cape honeysuckle is totally dead the roots will gradually rot. At first this will subtract nitrogen from the soil, but when they have totally disintegrated they will return the nitrogen and the soil will be good. This will take a few years. Thus, while you are growing the runner beans keep an eye on them. If they should turn yellow this means that they lack nitrogen. In that case fertilize with fish emulsion to keep them growing. Usually beans don’t need any kind of fertilizer, or mighty little since they make their own fertilizer, so only fertilize if you notice the problem with yellow leaves.

      Reply