What Is Shortstop?
Shortstop is a systemic plant growth regulator containing paclobutrazol as its active ingredient. When injected into the soil around a tree by our state certified applicators, it's absorbed through the roots and transported throughout the plant's vascular system.
Unlike pruning, which is a temporary solution that often stimulates more growth, Shortstop works with the tree's biology to produce lasting results. A single application is active for three years.
How Shortstop Works
Paclobutrazol inhibits the production of gibberellins, the plant hormones responsible for stem elongation and cell division. With gibberellin levels reduced, the tree stops spending energy on rapid shoot growth and redirects it to:
- Root development: a stronger, more extensive root system that improves water and nutrient uptake
- Defense systems: more resources available to fight off pests and diseases
- Canopy density: shorter internodes mean a more compact, dense crown
Benefits of Shortstop Treatment
Reduced Pruning Needs
Trees treated with Shortstop grow more slowly and compactly. For trees near power lines, buildings, or in tight spaces, this means significantly less frequent pruning, which translates directly to lower maintenance costs over the three-year treatment life.
Improved Drought Tolerance
A deeper, more extensive root system means treated trees handle Iowa's summer dry spells much better than untreated trees. This is particularly valuable for trees in urban settings where soil compaction already stresses root systems.
Stronger Disease & Pest Resistance
Healthier root systems and denser foliage make trees less susceptible to many pests and diseases. Shortstop is often used as part of our treatment programs for chlorosis and bur oak blight because it gives the tree the physiological resilience to respond better to other treatments.
Reduced Storm Risk
A more compact crown with shorter internodes is more structurally sound and offers less surface area to wind. Trees with controlled, dense canopies fail less frequently in Iowa's summer storms.
Enhanced Flowering and Fruiting
In some species, Shortstop can increase flowering and fruit production by shifting energy from vegetative growth to reproductive effort. Fruit tree owners sometimes see improved production in Shortstop-treated trees.
How Shortstop Is Applied
Our trained and state-certified team applies Shortstop by soil injection, the product is injected directly into the soil around the base of the tree, where it's absorbed efficiently by the root system. This is more effective than surface application because it reaches the roots immediately with minimal waste.
We apply Shortstop any time the ground isn't frozen, spring, summer, or fall. For trees receiving Mn-jet Fe chlorosis treatment in the fall, we typically apply Shortstop first, then inject the Mn-jet Fe as a combined program.
Great standalone treatment or powerful combo: Shortstop works on its own for any tree you want to slow down and strengthen. Combined with Mn-jet Fe injection, it's a transformative program for chlorotic pin oaks and river birches.
Is Shortstop Right for Your Tree?
Shortstop is appropriate for a wide range of trees and situations. It works especially well for:
- Trees growing under or near power lines
- Trees that require expensive pruning every 1–2 years
- Stressed urban trees with compacted soil and limited root space
- Trees recovering from disease, drought, or transplant stress
- Trees receiving chlorosis treatment (paired with Mn-jet Fe)
- Any tree where you want to slow growth and improve long-term vigor
Service Area
We provide Shortstop growth regulator treatment throughout Central Iowa, Roland, Story City, Ames, Boone, Nevada, Huxley, Ankeny, Gilbert, and surrounding areas.