One of the best places for outdoor activities in Ullerslev is Bondemosen, a green area in the heart of the town. Part of the area is owned by the local authority. Bondemosen's Cattle Grazing Guild has cattle grazing in the area during the summer. These unwitting "nature conservationists" help to preserve the characteristic plants of the area by keeping the grass and weeds down.
In spring, you may be lucky enough to see broad-leaved helleborine and western marsh-orchid on the moor.
There is parking in several places around Bondemosen, most centrally by the old town hall and the Ullerslev centre.