Hebe Heartbreaker

For some time now I have been trying to get a reasonable macro image of just one or two of the tiny branches of the Hebe Heartbreaker plant in one of our borders, set against the overall magenta hue of the plant However. because they grow so close together even with an aperture of 2.8 at 600mm I am unable to get such a limited depth of field. To see the problem look at my extra image which shows how the bush is just a mass of tiny branches full of leaves. My final image has had a bit of help from photoshop to sufficiently blur the surrounding vegetation.