If Your Roses Don't Get Enough Sun, They Will Not Thrive. Here Are Some Symptoms
by Bob Bauer
Does your rose bush have long thin spindly canes with leaves spaced far apart on them? Are the leaves on your bush smaller than they should be? These symptoms are a dead give away that your rose needs to have more sunlight. A rose that is receiving plenty of sun will have leaves that are larger and spaced relatively closer together.
Rose Problems Page
If your rose bush is growing in one direction only, it is a definite sign that it is in need of more light. What the rose is trying to do is to grow in the direction that the light is coming from, meaning that it is getting little or no light in the opposite direction. It is a good idea to either prune branches of trees that are in the way, or move this rose to a new location if you want your rose to thrive.
'All Ablaze'
If your rose bush has foliage that looks healthy and green, but you notice that it is producing little if any NEW growth, you probably have a rose that needs more light. Things to check for before making this diagnosis: (1) Is the rose getting enough water? Check regularly to see if the soil about 3 inches deep is contiuously moist. (Notice I said moist and not soaked! If the soil is waterlogged that is another reason that roses don't grow.) If the soil is moist only sometimes and dry the rest, you will see NO new growth. (2) Do you fertilize your roses every year at least once or twice? If you don't, this can cause your roses to not grow. A serious lack of nutrients can even cause your plant to drop all of its leaves.
Bottom line, if you have well watered and fertilized roses and they still won't grow, you can probably put the blame on lack of sunlight. You must either cut down the trees around it or move it. It will not get better
'Westerland'
Roses that don't flower much, or don't flower at all are usually stressed. There can be several causes of this stress. Lack of water or lack of proper nutrients are the most common causes. Lack of a sufficient amount of sunlight is the next most common cause of this condition. When a rose won't bloom, it is telling you that it needs all of its energy just to keep alive, and doesn't have enough left to reproduce. It is holding on until the conditions improve. If you have a rose in a semi shady location and it won't bloom you can pretty much take it to the bank that it needs more light. Move the rose, it won't get any better. Roses are least stressed when moved in the early spring before the spring growth spurt.
These are canes that grow and grow and get longer and longer and never form buds at their ends. This can be caused by many things, but one of them is definitely lack of light. The rose is attempting to 'grow into the light'. If you have a rose that used to flower normally, but is now producing blind shoots, you should consider checking the light level of its location. Sometimes as the years go by, you haven't noticed that a tree branch or shrub or perennial has grown to block the light that once reached the rose in question. Once blooming older roses can produce what appear to be blind shoots, but are really just the new wood that will produce the flowering branches of next season.