Darwiniensis wrote: In regard to the first plant: I agree that, without flowers, an id to species will be be difficult. However, there are a couple of things to look for which will help to narrow it down.
Tabernaemontana will have milky latex (family Apocynaceae). Gardenia do not have milky latex.
Check to see if your plant has interpetiolar stipules (see attached pic for an example). If so, it confirms that your plant is either a Gardenia or another genus in the same family (Rubiaceae) as interpetiolar stipules are a very reliable character of that family.
BTW the image is not mine (found on the net & used for illustrative purposes only).