Three experiments were conducted to test five combinations of Wulpak self-felting wool pellet mulch treatments for their effectiveness in controlling weeds and their influence on crop growth and survival during propagation and liner production. Treatments were Wulpak wool pellets, Wulpak treated with 7.1% copper hydroxide (Spin Out®), Wulpak treated with isoxaben (Gallery 75 DF), Wulpak and prodiamine (Factor 65 WG), and a control. Species used were Siberian bugloss [Brunnera macrophylla (Adams) Johnst.], Butterfly bush (Buddleia davidii Franch.), Spotted deadnettle (Lamium maculatum L. 'White Nancy'), Oriental poppy (Papavar orientale L. 'Carneum'), Hydrangea (Hydrangea serrata (Thunb. Ex J.A. Murr.) Ser. 'Blue Bird'), and Virginia sweetspire (Itea virginica L. 'Henry's Garnet'). Compared to the control, Wulpak suppressed weeds in five of the six species, and Wulpak with copper hydroxide reduced weed cover and weed dry weights in all species tested. The addition of isoxaben to Wulpak did not enhance weed control relative to Wulpak alone. Wulpak + prodiamine was detrimental to Hydrangea due to a phytotoxic response. Wulpak alone significantly increased total plant dry weight for Buddleia, Papaver, and Hydrangea compared to the control. Survival rates for the herbaceous species were higher for plants grown under control conditions relative to those treated with Wulpak, but there was no effect on survival of the woody species Hydrangea or Itea. In regards to the propagation study, weed cover and weed dry weight was significantly greater when cuttings were stuck through the Wulpak mulch prior to adventitious rooting. Crop survival plummeted to 37% when unrooted cuttings were inserted through the Wulpak mulch compared to 93% and 99% survival for the Wulpak applied after rooting and the control treatments, respectively. The use of Wulpak has potential to be an alternative, effective means of weed control, however, the problem of greater crop mortality must be addressed.

Key words: Brunnera macrophylla, Buddleia davidii, Hydrangea serrata, Itea virginica, Lamium maculatum, liner production, Papavar orientale, preemergent herbicide, Wulpak.