I am preparing a beef roast and I am looking for alternatives to potatoes and carrots to put in the roasting pan.

whole shallots and bulbs of new seasons garlic in the skins and just pop them out and serve with pan juices,i would serve the roast with a cake tin layerd with sliced root vegetables seasond with fresh time and melted butter and cook with roast turn out and slice cake shape

I was going to say fennel bulbs and celeriac and read puresugar's answer and she has said it al! My favoite things to roast.

Cipollini onions would also be nice. They go well with beef. You might even think about radishes.

Celery root's a great addition, as puresugar says. It tastes really lovely ... as do leeks, cut into chunks.

Sweet potatoes, butternut squash, garlic cloves, and/or fennel are my 'alternates'. What about parsnips, celery root, turnips...if you like them. Closer to finishing time, maybe mushrooms?

I roasted a chicken last night and roasted cauliflower florets and brussels sprouts with it. They only take about 30 minutes to cook, so toss them in near the end. They were glorious with a little marjoram. I would think rosemary would be nice with beef. So yummy.