The deal will see JKM managing director, James Spice, join the group as Head of Business Development.
Announcing the acquisition, TGCG Chief Executive Officer, Adam Brindle, said:
"As the Japanese knotweed industry consolidates, JKM is the perfect addition to our growing portfolio of services, that already includes our hugely successful Japanese Knotweed Specialists brand.
"I am very pleased to welcome James to the team. It's exciting for both our companies as we are able to take the best of what we share forward to help achieve further growth. The JKM customer base can now look forward to a broader offering that includes a full range of grounds maintenance, tree works, invasive weed removal and gritting services."
"I am delighted to be joining The Grounds Care Group at such an exciting time, there is already a fantastic team in place and the business has so much scope for further growth.
"When I met with Adam it was his drive and enthusiasm to grow, improve and add new strands to the business that proved the deciding factor."