The effects of tree guards and weed mats on establishment and growth of native tree seedlings, Thick-leaved oak (Cyclobalanopsis edithiae (Skan) Schott., Fagaceae), planted in an exposed hillside grassland in Hong Kong, were investigated. The natural regeneration of C. edithiae is poor due to a lack of seed dispersal agents and high seed predation, and therefore, this species is often targeted for forest restoration. The experiment lasted for 3.5 years during which the height, basal diameter, and crown diameter of individual seedlings were measured and survivorship recorded. The use of weed mats alone did not have a significant effect, but a combination of tree guards and weed mats led to a significant improvement in establishment, survivorship, and growth of the seedlings during the experimental period. Initially, the guards promoted rapid height growth of the seedlings, although lateral growth and secondary stem thickening were compromised. After the seedlings grew over the tree guards, the basal diameter and crown diameter increased at a notably faster rate. The combined effect of the tree guard and weed mat on the seedling growth pattern was found to be beneficial and contributed to the high survivorship of the seedlings. Comparing the survivorship data and the costs of various treatments, the use of tree guards in combination with the weed mats was demonstrated to be more cost-effective than planting the seedlings without tree guards or weed mats. The potential for applying the technique in afforestation programs with native tree species for forest restoration in Hong Kong and other tropical regions is discussed.