Pinching Back the Bleeding Heart or Glorybower

In a recent entry on inducing flowers on the bleeding heart, I mentioned the tip of pinching back the top sprouts.

The tip of "pinching back" on plants is nothing new. Although pinching does not guarantee flowers, it does induce the lower branches to grow rapidly, with some branches flowering in the process.


Here's a technical reference to "pinching back" from wikipedia.org with a background on Topping.




Topping

Is done by removing the top of the apical meristem (dominant central stem), called the apex or terminal bud, in order to transfer apical dominance (the tendency for the apex to grow more rapidly than the rest of the plant) to the shoots emanating from the two nodes immediately beneath the pruning cut. This process can be repeated on one or both of the two new meristems, when they become apically dominant, with the same results. This process can actually be repeated almost infinitely, but over-diffusion of apical dominance will produce smaller, lower quality buds, so it is usually done no more than a few times. Topping also causes more rapid growth of all of the branches below the cut while the plant heals.


Pinching

Pinching (also called super cropping) is similar to topping in that it causes the lower branches to grow more rapidly, but the apical meristem will maintain apical dominance, which is especially useful if the plant has already been topped. Pinching is performed by firmly pinching the apical meristem(s) so as to substantially damage vascular and structural cells but without totally breaking the stem. This will cause the lower limbs to grow more rapidly while the pinched tissue heals, after which time the stem will resume apical dominance.

From botany.com,

Pinching, Pinching Back, or Pinch Out:

To remove the growing tip of a plant, with finger and thumb, to encourage the production of sideshoots or the formation of flower buds.



Pinching out is also used when small side shoots are completely removed. This is done when single stems are desired, especially when training to form the "trunks" of standard (tree-form) specimens.

In other words, pinching back growing tips is done on certain plants to encourage bushing by inducing branching. This is especially when these plants have become leggy or unattractive with age.


How Pinching is Done

Although the procedure below discusses pinching on the Bleeeding Heart (Clerodendrum Thomsoniae), the technique applies generally to plants that can benefit from it.

Shown below is the Bleeding Heart (or Glorybower). Encircled in the picture is actually the forking of two branches that resulted from a recent pinching. With around 3 inches of growth, the new branches will be pinched back.


Position the thumb and forefinger to the new growth or terminal bud that is about half or one inch long. Grasp this terminal bud with the thumb and finger ensuring thumbnail is on its base.



This is the part that will be pinched off. Be careful not to include other leaves unncessarily.



Using the thumbnail and forefinger, pinch on to the soft fleshy base of the bud until it is cut. With a slight tug by the twist of your wrist, pull the pinched bud from the central stem (apical meristem).

Shown below is the terminal bud pinched out. Encircled in the photo is the pinched stem.


Eventually, two nodes would sprout from this.



Shown below is a couple of branches coming out.


In the pinching below, a raceme (rey'seem) or a cluster of flowers sprouted on one side.


Using the pinching technique, an otherwise lanky plant becomes bushier. Flowering is more likely then to occur in the new growth of the lower branches.



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