by B. Rosie Lerner
Purdue Extension Consumer Horticulturist
Poison ivy’s blister-causing agent
permeates entire plant entire yearQ: This winter, I was cutting down some trees that had poison ivy growing on them during the summer. I broke out in a rash, even though the poison ivy leaves were gone. Does poison ivy stay poisonous even after the leaves die? How do I remove the plants, even though they are already dead, without becoming contaminated? I am terribly sensitive to poison ivy and thought that I would be safe by waiting until winter.
The cause of poison ivy blisters, a compound called urushiol, is contained in the plant sap and can remain active even after the foliage dies back. The stems, trunks, and roots will also contain urushiol, which can remain active for five years or longer. So even dormant and dead plants can contain irritating sap. Of course covering the skin with gloves, clothing, etc., provides reasonable protection but you can pick up contact with the sap from protective clothing and tools!
Though there are many tales and testimonials of various home remedies and products, according to the FDA, there is no proven, consistent way to inactivate the urushiol. For more information regarding poison ivy rash and prevention, see http://www.fda.gov/fdac/features/796_ivy.html
. You might also consult an allergist for other advice on how to prevent/treat. Q: I have four large Christmas cactus, and starts were given to me from plants that were flowering profusely. Last summer, I put them outdoors under a large pine tree, and they grew very nicely. Then, about August, I brought them into the basement and around November brought them up, but they never ever bloomed. My sister has several, and they all bloom. What am I doing wrong or not doing right? Also, I have an aloe plant and wonder if it requires sun or shade. — Betty K., via e-mail
There appears to be much confusion about these unique tropical cacti regarding care, maintenance and, especially, on how to get them to re-bloom. So much so, that it’s the most frequently visited section of the Purdue Extension Web site.
Christmas cactus is a tropical type plant, not quite as drought tolerant as its desert relatives and, in fact, may drop flower buds if the soil gets too dry. The plants will wilt when under drought stress. Water thoroughly when the top inch or so of soil feels dry to the touch.
While the Christmas cactus can adapt to low light, more abundant blooms are produced on plants that have been exposed to more light intensity. Moving it to a shady location outdoors for the summer is fine, but it should be gradually accustomed to lower light when brought indoors. It could be that your plants suffered too drastic a change when brought directly to the basement.
Christmas cactus will bloom following a 6-8 week period of uninterrupted long nights of about 12 hours daily, (such as between 8 p.m. and 8 a.m.). Cool temperatures of about 50 to 55 F will also induce blooming, eliminating the need for the dark treatments.
For more information on Christmas and other holiday cacti, see: http://www.hort.purdue.edu/ext/cactusFAQs.html http://www.hort.purdue.edu/ext/christmas_cactus.html
. Q: I have had a Norfolk Island pine for decades and it has always been healthy. It is over 4 feet high and I really don’t want to lose it after all these years.
The tree had new growth at all of the tips of the branches and had a new row of branches at the top about 6 inches long already. A few weeks ago I noticed that there was a mushroom growing at the base of the tree. I have never seen this occur before. I removed the mushroom and about a week later the tree looked slightly droopy. Another week later, the tips of the branches were drying out and the new branches were also looking dry.
Three weeks after the mushroom appeared the tree is definitely dying. I have tried plant food spikes, watering, misting, but nothing has worked. I am afraid I am too late to save this tree. Is there anything I can do to save it?A:
Mushrooms growing at the base of outdoor trees is common, but not so on houseplants. Mushrooms typically grow on decaying organic matter, so when they are seen growing on the trunk of a tree, it is an indicator of decaying plant tissue. Some fungi will enter an otherwise healthy tree through a wound or pruning cut and cause internal decay. Based on your description, your best bet to save the tree is to take a cutting and discard the old decaying trunk.
Norfolk Island pine cuttings can only be taken from the top of the central leader stem; cuttings from the lateral branches will not form a new leader.
You’ll find more information about how to take cuttings at http://www.hort.purdue.edu/ext/HO-37web.html
More information on wood decay fungi is available at http://www.ppdl.purdue.edu/PPDL/weeklypics/8-29-05.html