What plant are you wanting to dwarf and what zone are you in? Need more details.

Zone 7
I want to dwarf morning clories

I do not grow morning glories so I have no idea. You might try posting on the Cottage Gardens or Vines forums. Those folks would be more knowledgeable about them.

pomme8916,

There are several plant growth regulators that reduce internodal elongation in a wide variety of plants, which is a dwarfing effect. These are usually sold to commercial plant growers who wish to keep their plants compact in small containers for sale. For that reason, these growth regulators are apparently not sold in retail quantities. But in case you want to use plant growth regulators to keep your morning glories short, here is some information on a few commercial products:

A-Rest, from SePRO, has the active ingredient Ancymidol, and it reduces internodal elongation in a wide variety of plants including container grown lilies, poinsettias, mums, tulips, bedding plants, and foliage plants in containers. It is for use in nurseries, greenhouses, shadehouses and interiorscapes. You should not use wetting agents in combination with A-Rest, because that may cause crop injury. A 1 quart bottle costs about $79.66.

SePRO has a new plant growth regulator called Topflor Plant Growth Regulator, whose active ingredient is Flurprimidol, but I don't know any details on how you would purchase it. Like most plant growth regulators, it apparently isn't available in retail quantities.

B-Nine WSG from Chemtura, has the active ingredient Daminozide and it is for use in commercial or research greenhouses, shade houses and nurseries. B-Nine will move systemically within the plant to reduce internodal elongation. Use it on mums, azaleas, hydrangeas and bedding plants to produce shorter and more compact plants. For best results, water before spraying plants. It is applied as a foliar spray. Foliage should be dry when B-Nine is applied. It is billed as a gentler option for plant growth regulation. A one pound bag sells for about $111.50.

The story is the same with any plant growth regulators that I know about. All are priced out of the reach of the home gardener. For example, Bonzi sells for about $154.45 a quart.

Hopefully some enterprising company will repackage these plant growth regulators in small quantities affordable to the home gardener, but for the time being I don't know of anyone who is doing that.

MM