The following varieties are prohibited for use on city streets in Waterloo due to hazardous thorns, weak wood, messy fruit, susceptibility to disease or insects, or undesirable growth habits:

Ash - Fraxinus species

Cottonwoods - Populus deltoides
Poplars - Populus species
Silver Maples - Acer saccharinum
Boxelders - Acer negundo
American Elms - Ulmus americana
Chinese Elms - Ulmus parvifulia
Siberian Elms - Ulmus pumila
Hawthornes - Crataegus species (Except thornless varieties)
Locusts - Gleditsia triacanthos & Robinia pseudacacia (Except thornless & seedless varieties)
Gingkos (female) - Gingko biloba
Russian Olives - Elaeagnus angustifolia
Firs - Abies species
Junipers - Juniperus species
Larches - Larix species
Spruce - Picea species
Pines - Pinus species
Douglas Fir - Pseudotsuga species
Arborvitae - Taxus species
Yews - Thuja species
Hemlocks - Tsuga species
White Birch - Betula papyrifera
Pin Oaks - Quercus palustris
Willows - Salix species (includes Austree)
Catalpas - Catalpa speciosa

Note: This list may be updated anytime