A fast-growing tropical native, shrimp plant is easily tip-pruned or pruned back severely, depending on the time of year. Two plants share the common name "shrimp plant," known botanically Justicia brandegeana or Pachystachys lutea (yellow shrimp plant). As both are members of the acanthus family (Acanthaceae), they have similar growing habits and form that can be pruned in like manner. By selectively trimming back leggy stems to a node, or location of a leaf pair, the plant with rejuvenate in a fuller form.
Determine which branches or stems need trimming back. If the entire shrimp plant is large and unruly, think about the size the plant should be after pruning is complete.
Snip off stems with the pruners (or landscape scissors) at a point no more than 1/3 inch above a leaf node--the point where a pair of leaves attaches to the stem. If you are deadheading (removing old flower clusters), follow the same guideline by snipping them off above a leaf node.
Reduce all stems as in Step 2 until the entire plant size meets your requirements. Avoid cutting back too deeply into semi-woody stems, as it will take longer for the shrimp plant to regrow and then flower.
Severe Pruning Instructions (for Rejuvenation)
Prune into the lower semi-woody stems of the shrimp plant, cutting back the entire plant mass to 12 to 18 inches tall.
Apply a light granular fertilizer at the next watering to boost the plant's response of creating new foliage.
Trim back the new growth's stems, if needed, to keep the plant uniform in shape as it rejuvenates. Be mindful not to trim the plant too much, since the flowers are borne on the ends of stems; you will prolong the time needed before the shrimp plant again comes into flower.