The Collaborative International Dictionary of English v.0.48:

Overgrow \O`ver*grow"\, v. t. [imp. Overgrew; p. p.
   Overgrown; p. pr. & vb. n. Overgrowing.]
   [1913 Webster]
   1. To grow over; to cover with growth or herbage, esp. that
      which is rank; as, dandelions have overgrown the lawn.
      [1913 Webster +PJC]

            The green . . . is rough and overgrown. --Sir W.
                                                  Scott.
      [1913 Webster]

   2. To grow beyond; to rise above; hence, to overcome; to
      oppress. [Obs.] --Mortimer. "O'ergrown with labor."
      --Beau. & Fl.
      [1913 Webster]

   Note: [Usually in the past participle.]
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Overgrow \O`ver*grow"\, v. i.
   To grow beyond the fit or natural size; to grow too large;
   as, a huge, overgrown ox. --L'Estrange.
   [1913 Webster]

WordNet (r) 3.0 (2006):

overgrow
    v 1: grow too large
    2: become overgrown; "The patio overgrew with ivy"
    3: grow beyond or across; "The ivy overgrew the patio" [syn:
       overgrow, grow over]

Moby Thesaurus II by Grady Ward, 1.0:

91 Moby Thesaurus words for "overgrow":
   bespread, blossom, branch, branch out, brew, bud, burgeon,
   burst forth, cover, deploy, develop, disperse, expand, extend, fan,
   fan out, fill, flare, flood, flourish, gather, gemmate, germinate,
   grow, grow over, grow rank, grow up, hypertrophy, increase,
   know no bounds, leaf, leaf out, leave, luxuriate, mature, mushroom,
   open, open up, outgrow, outspread, outstretch, overabound,
   overbrim, overdevelop, overflow, overrun, overspill, overspread,
   overswarm, overtop, procreate, pullulate, put forth,
   put forth leaves, put out buds, ramify, reproduce, riot, root,
   run riot, shoot, shoot up, spill over, splay, spraddle, sprangle,
   sprawl, spread, spread like wildfire, spread out, spread over,
   spring up, sprout, sprout up, strike root, superabound, swarm,
   swarm over, take root, teem, teem over, thrive, tower, unfold,
   upshoot, upspear, upspring, upsprout, vegetate, wax, widen