|The back part of my yard used to be forest. Vines with thorns grew among the roots. How do I kill them-they spread underground with woody roots,leaves are glossy,heart-shaped.|
|The pest is smilax (deer thorn, catbrier), one of the toughest perennial vines with which a gardener has to contend. The thorny vine with waxy, heart-shaped leaves wends its way through azaleas, English laurel and perennial flower beds with impunity. Smilax has berrylike fruit that birds enjoy --- but this vine is no joy to control.
As the smilax begins to grow from seed, it sends up a single shoot and produces an underground bulb. As the plant matures, a large cluster of bulbs is created. Only a few shoots will arise from the root mass; the majority of the bulbs lie dormant. If you kill one shoot, that bulb may die, but adjacent bulbs may send up shoots within a few days.
Greg MacDonald, Extension weed specialist, says control of smilax should focus on early detection and control before more bulbs are formed. If you find this noxious vine, better to dig it up rather than chopping it down.
Try to get all the bulbs out of the ground. The only other option is frequent sprays of a weedkiller like Roundup or Brush-B-Gon. Eventually the root mass will be depleted, but the process may take months, even years.