On a repeat-blooming rose you always want to dead-head for best repeat bloom. On some rugosas the hips are very pretty and some people leave them on toward the end of the blooming season for that reason. I don't know whether Grootendorst has pretty ones that are worth leaving on.

This is a fairly vigorous rose and some gentle pruning in order to give the bush a better shape shouldn't hurt it, and you'll have a more attractive rose to look at.

Ingrid

Gmcaw85, I've been looking for a white Grootendorst, but recently learned that Burling has the pink one. Do you have a photo you can share?

Thanks,
jannike

I wouldn't do any major pruning before spring. At that time you can do pretty much anything you want to make it look decent.

Deadheading is up to you. I don't think Grootendorsts set hips. Either way, if they are ugly and you want to get rid of them, get rid of them.

These are not small plants. Hopefully it was planted in a place that can accommodate something that can get 6 x 6 ft.

Grootendorst seem to handle almost anything. It doesn't set hips and you can safely deadhead clusters. I usually prune mine in spring and only light clean up later in the season. I doubt you need to worry too much about hardening off for winter with the hardy rugosa varieties. If they loose some of the tender new growth when winter comes, it doesn't affect the plant much, and it will grow back quickly in spring.

Thanks for the replies everyone! Im thankful its such a durable plant, the house was vacant for close to 3 years so luckily it is still blooming!
Attached is the picture, it has grown so much since I cut it down in Spring, its now about 5ft, but as you can see its over all shape is unattractive, I didnt really know what I was doing and left anything that looked alive on the plant alone and the old thick dead wood I sawed off, the result now is a very uneven plant.

I really don't think it looks that bad at all; the leaf cover helps to disguise the shape. Looking at it now I wouldn't do anything to it until the regular early spring pruning. I think it's rather pretty, and it really looks healthy. You've done a great job on it.

Ingrid