Polygala garcinii is a multistemmed, resprouting shrublet reaching about 40 cm in height. The branches are slender and erect or trailing.
The linear to needle-like leaves adhere to the stems. Leaf dimensions are up to 10 mm long and about 3 mm wide.
The dark pink to magenta flowers are white-crested, growing in stem-tip racemes among few leaves. The lateral sepals are hairy on their lower surfaces. Flower diameter is about 15 mm. Flowering happens from winter to spring.
The species distribution is in the Western Cape, extended slightly into the southwest of the Northern Cape in southern Namaqualand and the west of the Eastern Cape.
The habitat is fynbos and renosterveld slopes and flats in clay or sandy soils. The species is not considered threatened in habitat early in the twenty first century (Curtis-Scott, et al, 2020; Vlok and Schutte-Vlok, 2015; Manning, 2007; Bond and Goldblatt, 1984; http://redlist.sanbi.org).