Question
rose photos
Lynette,
Another knock-out question, but would appreciate your help. Row of two year old bushes and each year around august they turn their leaves yellow--->brown---Drop off. Now the end of some of the stems are dying and falling off. I believe they are getting adequate water. I've sprayed them with fungicide. I've treated with a little iron. Help?
AnswerI get a lot of questions about Knock Out roses and in my opinion, they will re-act to some sprays. People have said that they have used a certain spray to get rid of bugs or a disease and it has nearly killed the rose bush. They really isn't a need to spray for black spot at the end of the season as the leaves are going to die and drop off anyway. In regards to water. Roses need about 5 gallons of water every five days. That is roughly about one bucket of water. If they are on a drip system and the emitters are one gallon per hour, they have to be on for at least 5 hours. Just to give you an idea of how much they need. Ideally drip systems should be changed to a five day five hour pattern when the weather gets hotter. For roses it can be left at 5 hours all summer. Also, if the leaves die at the bottom of the rose bush, this is the rose getting rid of older leaves. However if it starts at the top and move down, there is something wrong with the roots such as not enough water. Black spot will not kill a rose it only makes it look ugly so if the problem isn't too bad, I wouldn't use a spray. If it is really bad try changing your fungicide and see if that is the thing that is making the rose drop it's leaves. The dying is a problem with the roots and I think it is not enough water.
