Orchid Culture - Questions & Answers from This Month

Not Many Flowers

Q. I have a healthy, good-sized C. Tropical Pointer 'Cheetah' that has beautiful flowers, but it is a poor bloomer, i.e. few flowers for its size. This year, it managed only two. Are spotted orchids are often like this? It does have C. aclandiae in its ancestry, a well-known curmudgeon. More light? Raise it up, or will it always be stingy?
A. I don't think the spotted orchids as a whole are reluctant bloomers. In fact, Ron Midgett from New Mexico got a cultural award on Tropical Pointer 'Cheetah' with 55 flowers. Cattleya aclandiae can tend to lower flower count, but it is pretty far back in the family tree. One of Tropical Pointer's parents is intermedia which can throw off tons of flowers. I'd say move it up into brighter light and see if you don't get rewarded next year.   (Jul-26)

Heat Damage or Something Else

Q. I hang all my Catasetinae in nearly the highest point in my greenhouse. Is it possible this marking is due to sunburn or heat? The catasetum tested negative for virus. There are a few others just leafing out which look similar but at least two that look normal with no leaf streaking.
A. The heat scorch makes sense, the leaf temperature got so high that it damaged the chlorophyll just short of burning the leaf. Keeping a max min thermometer handy in strategic locations will tell you how hot or cold your growing area has gotten. Heat scorch explains the chlorotic streaking on the leaves, but there is also fine dotting on the leaves toward the tips, so I asked Janet to send a pic of the leaf underside. When catasetum leaves are young and tender, they are thrips magnets and you can see the bulls eye pattern on the leaf undersides from thrips feeding on the leaf. I do a bimonthly drench with Orthene (1 tsp/gal, same as for spraying) and thankfully I haven't seen thrips damage for several years. It also keeps the scale and mealys gone.   (Jul-26)

Repotted Dendrobium Leaf Yellowing

Q. I repotted this orchid last month into lava rock and charcoal. It had been in a mixed mix. It’s two pieces, one is totally turning yellow leaf by leaf and the other one has new growth at the bottom. I guess one doesn’t like the new mix?
A. It looks like the growth to the left in the picture is dying, so I would remove it from the pot. The one to the right in the picture should have had the oldest part of the plant flush against the edge of the pot so it would have more room to expand in the future. If the potting mix was radically different, the old roots may not acclimate. If there is new root growth, leave the plant alone to recover. If there isn't, remove the one piece and resituate the other, and consider whether the pot size is right. You'll want about 3-4 years in the pot, and the canes grow pretty closely together.   (Jul-26)