@Whale said:
…and shouldn’t that solution be something initiated by the Executive Committee on behalf of all Proprietors and not an expedient solution to appease one Proprietor…
Absolutely. The EC should make it clear that the one proprietor did not have the right to annex common property. The EC could put it to a vote of the OC to choose either to take advantage of the situation to have a community garden partially established at no cost or effort them or to require the one proprietor to reinstate the previous garden style. This would make it very clear to owners generally that annexing common property is not tolerated.