Issue: November 1, 2003

Broken dendrobium orchid

A potted dendrobium orchid fell from its perch and several stalks broke. These pieces are large and have good green leaves. It seems a shame to throw them away. Can I get them to grow roots?

Since you are growing orchids, you know some of what I will say in answering your question, but some readers will not know these facts.

Orchids have many growth forms. Some like vines grow upward from a single growing point. Others grow much like irises from a rhizome (a horizontal stem) that produces "upright" stems or pseudobulbs on which leaves and flowers are produced. Growth resumes from a bud at the base of the pseudobulb or stem. Most dendrobium orchids have this rhizome type of growth. The rhizome is the part of this plant from which roots usually grow. Roots only form on the pseudobulb when a bud produces a baby plantlet along the pseudobulb or on a flower scape.

Unless the broken parts have some of the rhizome attached, they will not be able to produce roots and should be discarded. If you think there is enough of the rhizome attached to the broken plant parts, you can pot the broken pieces or place them on some moist sphagnum moss in an open plastic bag to see if the roots will form. If they form, then you can pot the new plants.

Gloxinia died

I was given a beautiful gloxinia for my birthday. It grew and flowered beautifully, and then suddenly it died! What did I do wrong?

I hope you haven't thrown your gloxinia away. The gloxinia has a period of dormancy following flowering. The plant seems to die to the ground, but there is a large tuber remaining under the soil. After a period of rest, new leaves will be produced, and flowers will appear a few months later.

During the rest period (if you haven't already discarded the pot and soil), reduce watering. You don't want to completely desiccate the tuber but provide only enough moisture to keep the tuber from shriveling. If you water too much, the tuber will rot. When the time of dormancy has past, new growth will develop and you can increase watering in proportion to the growth of leaves.

Send gardening questions to Southwest Yard and Garden, Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu or at https://www.facebook.com/DesertBloomsNM/. Please include your county Extension Agent (aces.nmsu.edu/county) and your county of residence with your question!

For more gardening information, visit the NMSU Extension Horticulture page: desertblooms@nmsu.edu.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, office: 505-865-7340, ext. 113.