If a bulbous plant suddenly appears in isolation from the original
planting, it may have been relocated by moles, which can tunnel long
distances without emerging and move soil and debris without eating
bulbs. I don't know if squirrels dig up bulbs and replant them, but they
frequently dig up acorns and other nuts buried by another squirrel and
move them. Janet mentions Triteleia laxa as a vigorous spreader; most of
the western American Themidaceae ("themids"), including Triteleia,
Brodiaea, and Dichelostemma, spread readily by both offsets and seeds.
The heavy offsetting may be an adaptation to predation by digging
animals, which eat the big corms and leave the offsets. The "rice grain"
bulblets of western American Fritillaria species are similarly
effective. Not many people would object to Tulipa clusiana spreading,
but I recall it doing so in my mother's garden, not far from where Janet
lives. And I'll add to this list Lilium lancifolium (tiger lily), which
produces black bulbils in the leaf axil; they drop off and form new
plants quickly, which may offend you if you don't like seeing a lot of
orange lilies at the end of August.
Jane McGary, Portland, Oregon, USA
On 12/13/2025 5:40 PM, Janet Hoffmann via pbs wrote:
> I have spent the past couple seasons in my San Jose area, California garden ripping out some Ferraria crispa that started going crazy after about 3 years in the ground. I belatedly read that they are invasive in Australia.
>
> I have also become careful to cut off the seed heads on Homeria, Crocosmia, Allium unifolium, Amaryllis belladonna, Hyacintha hispanica. Freesia laxa and Tulipa clusiana. This seems to keep them from spreading beyond the clumps where they are planted.
>
> I had Oxalis purpurea in the ground for over 20 years before the clump started spreading rather vigorously. They are now coming up in an area across 20’ of concrete from the location where they were planted and I am not sure if animals are spreading the bulbs being as I don’t see seeds on them.
>
> The CA native Triteleia laxa can also spread rather vigorously from bulbs offsetting, not from seed or animal dispersal.
>
> Having this discussion of potentially problematic plants and how people keep them under control is helpful.
>
> Janet Hoffmann
> Campbell, CA
>
> _______________________________________________
> pbs mailing list
> pbs@lists.pacificbulbsociety.net
> https://lists.pacificbulbsociety.net/cgi-bin/…
> Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net>
> PBS Forum https://…
_______________________________________________
pbs mailing list
pbs@lists.pacificbulbsociety.net
https://lists.pacificbulbsociety.net/cgi-bin/…
Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net>
PBS Forum https://…