My Montauk daisy is huge, 3 people could not surround it, when and how much can I cut it back? Just coming out of a really cold Ct. winter and due for more snow his week. Some of the new buds are already showing. Help!
It is now late February. The best time to cut back the Montauk daisy (Nipponanthemum nipponicum) is in late spring or early summer, in order to keep it compact and encourage best blooming. If you cut it back to around 7.5-15 cm (3-6 inches) in height in May, there should be lots of new growth, so much that you may want to cut it back by half again around the end of June. This should prevent it from getting leggy and falling over from its own weight.
Your description of the plant’s size makes me wonder if it is time to divide the plant. For example, has the centre of the plant started to die out? If so, you can divide it in early spring when new growth appears. Deeply water it the day before, loosen the soil around the clump’s perimeter and lift the plant out of the ground, taking care to avoid damaging roots. Gently pull the roots apart with your fingers, and divide the clump into two or more plants. Each division should be at least 15 cm (6 inches) square. If there are any attached or stubborn roots, cut through these with a clean, sharp knife. Plant each new plant in a bed at the same depth as before and add at least 5 cm (2 inches) of compost. Space the plants at least 60 cm (2 feet) apart. Note that the plants may not flower as much the first year after division. Divide the plants every 2 to 4 years.
I see that you are writing from Connecticut. We are located in the Toronto area and generally respond to questions from Ontario gardeners. In the future, you may wish to contact groups that may have information that is more specific to your gardening region, e.g., the Connecticut Master Gardener Association or horticultural society (e.g., the Connecticut Horticultural Society) in your area.