Kahili ginger is finished blooming, and should get cut back once the foliage succumbs to frost.

Many plants are deciduous in autumn and winter, which means that they defoliate or die back, and then refoliate or regenerate in spring. Many others are evergreen, which simply means that they are always foliated through all seasons. What many people do not realize is that evergreen plants replace their foliage just like deciduous plants do. They just do not do it in such distinct phases of defoliation, dormancy and refoliation.

Tropical plants like cannas and some of the various begonias really have no need for formal defoliation, since they are from climates that lack winter. In the wild, they continually and systematically shed old stems as they produce new stems. Locally, they tend to shed more than they grow during late autumn and winter. The large types of begonias tend to keep their canes for so many years that it is not so obvious. Where winters are colder, cannas freeze to the ground, only to regenerate from their thick rhizomes as winter ends.

Zonal geraniums may seem rather tired this time of year for the opposite reason. They expect late autumn weather to include frost that would kill them back to the ground where they would stay relatively dormant until warmer weather after winter. Just because their foliage is instead evergreen through winter does not mean that it should be. It lingers and often becomes infested with mildew and rust (fungal diseases) that proliferate in humid autumn weather.

However, zonal geraniums need not be pruned back just yet. Even if they eventually get damaged by frost, pruning should be delayed so that the already damaged older foliage and stems can shelter the even more sensitive new growth as it emerges below. They can get cut back after frost would be likely.

Evergreen pear can get very spotty once the warm weather runs out because the same damp and cool weather that inhibits its growth also promotes proliferation of the blight that damages and discolors the foliage. The damaged foliage eventually gets replaced as new foliage emerges in spring, but will remain spotty and discolored until then. Photinia does not get as spotty, but holds blighted foliage longer into the following summer. Ivy can be temporarily damaged by a visually similar blight.

5 thoughts on “Dormancy And Defoliation Are Advantageous

    1. There happens to be a single tiny rhizome of Kahili ginger out there that I could send if you like. It is smaller than a wimpy bearded iris rhizome, but might do well if potted through this first winter. You can send your address to lghorticulture@aol.com, and then send a message here so that I know to look for it.
      If you like I can add a few other odds and ends. There are a few small but healthy rhizomes of an unidentified bearded iris that I pulled from one of the landscapes. While deadheading a mix of cannas, I collected a few seed. (I suspect that most are from the more prolific Canna indica rather than the mostly sterile hybrids. Because I did not have plans for them, I did not bother to keep them separated.) There are still some of the Amaryllis belladonna seed, which are too abundant here.

      Liked by 1 person

      1. Thank you so much for the offer. It is actually easy to get them here, I just have not gone shopping. One of my favotite things is reproducing plants any way I can and I am running out of room. I have started planting gingers outside of their beds in any space I can find. The future owner of this house will have a jungle to cut down.

        Liked by 1 person

      2. I sort of figured that, if you can get the other gingers, you could more easily get this one. Since I met this one here only a month or so ago, I have been wanting to bring more back from Southern California. I should have just ignored it.

        Liked by 1 person

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