Your photo doesn't appear, but if it's what I think it is, you can cut it back to the height you want, and it will sprout again from there. I did it with mine, and used the top bit as a cutting.

There are 2 plants that I know of which have the common name umbrella plant: the first 1 is Cyperus alternifolius, which should be grown in john innes no2, and stood in a saucer of water, or grown as a pond marginal in places where the temperature doesn't drop below 41 deg f, the second is Schefflera actinophylla, or queensland umbrella tree, which I think is what Hywel is thinking of, and his advice is correct, it needs a minimum winter temp of 55 deg f, and is grown as a houseplant, or in a warm greenhouse, Derek.