A plant container stabilizer. The stabilizer has a frustoconical body formed by a hollow wall. The body includes an open top in which a container for a plant can be disposed. Ports are provided along the exterior of the body to enable installation of a ballast material into the hollow wall. A collar is provided about the open top of the body and includes bayonet-style slots disposed therein. Tabs may be provided on an exterior sidewall of the container for engagement with the slots of the collar to provide a locking engagement between the container and the stabilizer. The wide base of the stabilizer and the added weight provided by the ballast material increase the resistance of the container to tipping or toppling over such as when subjected to winds. The stabilizer is further configured to enable nestable stacking of a plurality of the stabilizers for shipment or storage.
