Rose periwinkle (C. roseus `Little Linda'), a common bedding plant, grown in Hoagland solution #1 with Fe-EDTA at 5 mg/L Fe had normal shoot morphology, but abnormal root morphology. The primary root was twisted and lateral roots were extremely stunted with dichotomous branching. Over a dozen other bedding and foliage plant species had normal root morphology when grown in an identical solution, and cuttings from periwinkle with abnormal roots produced normal roots when rooted in 2 mM CaCl2. When these rooted cuttings were grown in Fe free Hoagland solution #1, root morphology was normal, indicating that the Fe-EDTA caused the problem. Seedlings were then grown in solution for 30 days with Fe supplied as Fe-EDTA (both 5 mg/L and 1 mg/L Fe), Fe-DPTA (5 mg/L and 1 mg/L Fe), Fe-EDDHA (2.75 mg/L and 0.55 mg/L Fe) or Fe2O3 (1 g/L). Solution pH for all were in a normal range of 4.8 - 5.6 Only the seedlings grown with Fe2O3, Fe-EDTA (5 mg/L Fe) and Fe-DTPA (5 mg/L Fe) developed abnormal root structure. All others had normal roots.