Knowledgebase

Clematis Question #751565

Asked May 23, 2021, 12:13 PM EDT

Please see my photo of the clematis. It bloomed late April/early May, I'm not sure what type that is. But you can see in the pic that everything it at the top and it has nothing at bottom (dead and brown stems). When would I prune this type of clematis and how far back should it be pruned? Thank you.

Anne Arundel County Maryland

Expert Response

Clematis is divided into three types: early bloom in the spring, mid-summer bloom and late or fall blooming. Since your vine started in April and you don't know it's name, I'm going to assume that it is in group 1 of clematis which means it should be pruned as soon as it's finished blooming. Prune back to 6 inches from the ground. 

It looks like you have wild grape also growing amid the bare stems. Take this out now.  The soil is moist which should facilitate removal.

furmar Replied May 24, 2021, 12:02 PM EDT

 

Thank you so much.  Thought it looked like something other than the clematis was growing in there also.  I really appreciate your help.

 

The Question Asker Replied May 24, 2021, 4:41 PM EDT

Thank you for your response below.  The vine still has one or two blooms.  At what point in the year is normal to cut this back?

 

Thank you. 

The Question Asker Replied August 24, 2021, 9:10 AM EDT

Clematis pruning can be complicated, but only when you want to preserve as much bloom potential as possible. We'll try to outline it with some clarity.

Within the group of clematis that bloom in spring, there is a fairly large subset that re-blooms in late summer to early autumn. Many of the popular and widely-available cultivars fit into this category, because this twice-blooming feature is a desirable trait. Several modern hybrids, though, are developed to bloom almost continuously all summer. Due to these reblooming abilities, there are two options for trimming technique.

Without knowing this plant's variety name, it will be difficult to determine which exact subgroup this plant belongs to, but close observation might reveal hints. Due to the timing of flowering, it's definitely in what's referred to as pruning group B (equivalent to group II when the Roman numeral system is used by some nurseries). Whether it's subgroup B1 or B2, though, remains to be seen and has some impact on how and when trimming best takes place.

If you see blooms opening now on the youngest growth only (uppermost parts or tips of the stems), it belongs to group B1. If blooms appear on both the youngest plus the older growth, it belongs to group B2. There might be some overlap nowadays with how many clematis hybrids exist, but usually, varieties that bloom approximately April or May into June, then stop flowering, and then bloom again around September are in B1. Varieties that bloom June through September, more-or-less nonstop, are B2.

For a B1 variety, lightly prune back some stems in spring, just after flowering. (You can do this earlier in spring if you don't mind losing some of those earliest flowers.) If you want to refresh an overgrown or leggy plant, occasional hard pruning (closer to the ground) in spring will result in blooms only during that second window, around September, because it will be the current season's growth budding at that point. (All the old growth buds would have been trimmed off by the early spring cutback.)

For a B2 variety, you can either prune like the above or cut the plant back harshly in early spring. A harsh cutback in this situation will also eliminate some of the earliest flowers, but since plants can bloom on current growth in-season as well, the overall bloom reduction won't be drastic.

You can always opt to ignore the group details and just trim the plant back harshly once every several years if you juts want to refresh it's look. You could also try a hybrid method of pruning, where you cut some stems all the way down near the ground and trim others only lightly. This mixture is the hardest method, though, since stems get pretty tangled as the plant ages and it can be nearly impossible to get those cut stems pulled out. The nuance in blooming type will simply tell you when to expect it to be able to bloom again based on how you trim - flowers will either appear later that same year, or one or two years later if it first has to re-develop older wood.

 

Miri

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