Not only yellow caps brown, and red caps too. I have a brown cap I have grown in a container for 9 years. Comes from Ontario. It is wild plant. Never shows any sign of disease or virus infection. I have seed from yellow and red caps but that is not for trade. You can see photos of the brown cap here
https://growingfruit.org/t/black-raspberries-in-october
So I have a number of blacks in the yard and Mother Nature seeing my crosses did its own and I have a purple cap and to boot its primocane fruiting
Yesterday I planted a tip root to this one hoping for a backup. Original came up in a pot next to a black currant. Looks fine, third leaf this year. What’s interesting is most purple raspberries and this is a purple Niwot x unknown red or yellow. Or Lynn’s or Sterling black x unknown Rubus idaeus. Most are described as having a bland flavor. These purples taste like boysenberries. Except they are much sweeter, in other words excellent flavor!!
I could see if the yellow tip rooted in a surrounding pot or dig one of the crowns out. I need to restart one in a new fabric container. This one has been in there 9 years or so. Here it is right now. Dark canes are dead canes from last year. Canes are yellow to green. You can see it’s prolific even after nine years.
