Question
my cactus
What kind of cactus is this? I'm really desperate, I've been poking around for hours but I haven't found any definite information. Please help!
Answer
Melocactus
Dear Emily,
I believe you have a young melocactus there. When mature it will develope a cephalium, a wool- and bristle-coated structure at the apex of the plant. They can take a long time to mature and are somewhat difficult to ID until they do. The cluster of spines at the top of your cactus precede the cephalium. They are slow growers and can take 7 or more years for the latter to develop. Their characteristic cephalium and are charctristic only of Melocactus, and the similar genus Discocactus. This is a permanent, apical, hatlike appendage. Cylindrical, with a diameter distinctly smaller than that of the plant body below, the cephalium will keep growing for the rest of the plant抯 life, but the body of the plant stops growing the moment the cephalium starts to form. As the plants age the cephalium doesn't increase in circumference it will steadily grow taller.
I don't know specifically which of the approx. 40 plants in the Genus you have but if you have time google it and see if you can find yours. It's hard when young to ID.
Cultivation: These cacti are not the easiest things to grow and aren抰 generally plants for beginners. I rarely pay attention to that warning, sometimes to my regret.
Melocactus grows from April to October, it can抰 endure long stretches of total dryness, and also too much water will rot it, as its weak root systems tend to be inefficient at sucking up water from wet soil. Nonetheless, again as a result of their tropical origins, they need a fair amount of water, but allow the soil to dry quite a bit before watering again. Melocactus rests from October to April but can抰 stand cold, or even fairly cool temperatures, tho I do keep mine in a room that is about 50-60 degrees and DON'T water it when it is dormant. It isn't the hardiest of plant so can't tolerate the very cold temps that most dormant cacti can. The literature says they prefer prefer more frequent water in winter than other cacti, say once a month. I just mist mine, but perhaps you should go by the literature. Do not feed in winter.
Since the root system is weak it generally resents being repotted and can take a long time to re-establish. The soil mix should be very quick draining, prefers very bright light, not as much as the most arid growing cacti, but plenty nonetheless. How long has yours been in that pot? If more than a couple of years I WOULD repot and put it in a smaller, azalea type pot at that.
Let me see if I can attach a picture of a mature plant (not yours specifically). If it doesn't come through, they are easy to find on the net.
So don't feel bad for all that poking. Young plants look like lot of other barrel cactus.
Hope this helps.
Maureen
