I have a problem in getting M. wolfii to flower. Flower buds are being produced, they grow somewhat and then they shrivel. This happened this year as well as last year. Does anybody have an idea what the cause might be? Too much water, not enough water, too much heat or sunshine, not enough heat or sunshine?
On the cultivation of this very tricky wrightii form:
For many years I had tried to grow this wrightii form from seed, but usually the seedlings rotted away. Finally, I managed to grow 3 plants to flowering size and I obtained fruits from them. One of the 3 original plants (sown in 1991) still survives, the other two died a few years after flowering. In addition, I have a number of seedlings from the harvested seed, a few of them have reached flowering size. These plants, just like the old mother plant, have those shrovelling flower buds.
I grow this form, just like all my Mammillarias, in pure pumice, and they are doing quite well in this 100% mineral soil. In the summer they can have a good amount of water, but not on cloudy and cool days. Cold in the winter (even a little frost) is no problem at all for them.
Wolter, Assen, The Netherlands.