Have a broom that is far to big.

Dont cut it to ground level you will be cutting into old wood and it will never recover,if its bare at the bottom, i dont think you can do much with it, if you buy another make sure you trim it after it flowers in its first few years, that will encourage it to branch from the bottom. hope this helps,

Does it set seed? There may be seedlings in the nearbye ground.

You may be able to thin it out by taking out some of the large branches to ground level, but this will not do the shape any good.

Cuttings are dead easy of non flowering shoots almost anytime. They are short lived plants in any case. And they will not shoot from brown wood only green. Saw a good selection of colours n sale today for less than £3 per plant and I am sure I have seen them cheaper than that.