Ideally select a plant with small leaves and a flexible single stem that can be trained to form the trunk. All is not lost, however, if there are multiple stems emerging from the base because some of the most stunning mop tops are produced when two or more stems are twisted into a spiral or plaited.
Gardenias (pictured below) are popular choices, as are box plants and ornamental figs. Some climbing plants – such as the easy-to-grow and attractive star jasmine (Trachelospermum jasminoides) – can be trained into a lollipop shape with the main supporting stem(s) twined around a stake. Westringia, the native rosemary, brings an attractive grey-green note to the garden and gives it a Mediterranean feel. A similar effect can be achieved by using more traditional plants such as olives and some of the taller-growing lavender varieties.
Duranta, the pigeon berry, is a favourite mop top choice in warmer climates. The Mop Top Robinia is widely planted but watch for its tendency to produce unwanted suckers from the roots.
After selecting the plant, choose the main support and remove other unwanted branches and shoots. Tie the stem to a stake but remember to watch that the tie itself doesn’t become a cincture as the stem thickens. Replace when needed or use a tie that allows for expansion.
Pinch out the growing tip at the top of the plant. This will encourage the development of the sideways growth that will form the ‘mophead’ part of the mop top. Then trim all over to begin shaping the head.
Watch out for new shoots emerging from the stem – the most effective way of removing these is to rub them off with your fingers while they are as small as possible.
Because of its shape a mop top is naturally top heavy, so potted specimens should be kept in a wind-protected spot.
Keep the head clipped into a perfect ball shape by using a plastic hula hoop as a guiding template.