On the legacy bulb wiki pages Kathleen Sayce reviews bulbs that outlast their gardeners, with some hints as to why. Suggestions came from PBS list members, review of world weed lists, USDA PLANTS National Database, Flora of North America, and some university databases. For more information consult Legacy Bulbs Index and Introduction.
Information about Trillium and species of other genera though Zephyranthes can be found on this wiki page. Information about other species is found on the pages linked below:
Albuca through Amaryllis - Anemone through Chionodoxa - Colchicum through Erythronium - Freesia through Hyacinthus - Ipheion through Iris - Ixia through Lycoris - Merendera through Nerine - Ornithogalum through Sternbergia
Trillium is a genus of 40-50 species native to North America. Species easily persist in shady woodland gardens long after planting, where growing conditions are suitable, and across a wide range of zones. For success, pick species that grow naturally in a climate that matches yours, and provide woodland growing conditions.
Tristagma uniflorum, syn. Ipheion uniflorum, spring starflower, persists and can be invasive in mild climates. Native to Argentina and Uruguay, this geophyte grows in WHZ 6-10. It thrives in sunny well-drained situations; it is winter-growing, spring-flowering and summer-dormant. States where this species has naturalized or established include Oregon, California, Texas, and southeastern states to Virginia.
Tulipa is a large genus of about 150 species, native to Eurasia and North Africa. Tulips tend not to persist for more than a few decades after a garden’s decline because they lack toxins that make many other bulbs unpalatable. Squirrels and mice are known to eat tulips. Nonetheless, several species tulips naturalize in gardens and may outlast their gardeners, where hybrids quickly vanish. This is due in part to seed set, which allows species to move around a bit, perhaps finding optimal spots in which to grow. Hardiness varies by species; cultivars are typically hardy in WHZ 6-9.
Tulipa clusiana, lady tulip, is native to eastern Europe and Asia, and has naturalized in California. Native to areas with summer drought, it seems to appreciate a sunny summer location where bulbs can bake in dry well-drained soil; WHZ 3-8. It has been in cultivation for hundreds of years.
Tulipa gesneriana, Didier’s tulip, has been noted from Ohio and Massachusetts. Its origins are unknown; it is probably from western or central Asia. Tulips attributed to this species in Europe are probably clones.
Tulipa saxatilis, candida tulip, is native to Crete, Rhodes and southern Turkey; like many other Mediterranean bulbs, it prefers dry summers in well-drained soils; WHZ 6-8. It has been in cultivation for centuries. It needs a hot sunny position and dry summer soil. Tulipa saxatilis ssp bakeri is native to Crete; the form 'Lilac Wonder' is most often seen in cultivation.
Tulipa sylvestris, wild tulip, like other partially rhizomatous tulips, naturalizes in woodland sites. It has been noted in states and provinces around the Great Lakes in PLANTS database. Expect it to persist widely in gardens; WHZ 3-8. It is native to Europe.
Watsonia is a South African genus. Plants are either winter growing and flowering, or summer growing and flowering; WHZ 8-10. Several are considered noxious weeds.
Zantedeschia is native to southern Africa. A stately arum lily, it has been grown as an ornamental for several hundred years. Two species are in the PLANTS database as naturalized; WHZ 8-11.
Zantedeschia aethiopica, calla lily, has been reported from Oregon and California, and Australia; it is widely grown in the British Isles. Despite the name, it is native to southern Africa. Expect it in other states, in wet locations and mild winters.
Zephyranthes, rain lilies, were mentioned repeatedly by southeastern gardeners. No surprise, this genus is native to southern North America, into Mexico and South America. Garden plantings across the south naturalize easily and persist for decades. Species mentioned by PBS members as easy to naturalize in gardens, and persisting with little to no care, include:
Species listed on other legacy bulb pages can be found alphabetically by clicking on the links below or by going to the index and introduction page where they will be listed in a table.
Albuca through Amaryllis - Anemone through Chionodoxa - Colchicum through Erythronium - Freesia through Hyacinthus - Ipheion through Iris - Ixia through Lycoris - Merendera through Nerine - Ornithogalum through Sternbergia - Legacy Bulbs Index and Introduction