Katandra hosts four species of boronia – B. mollis, B. ledifolia, B. pinnata and B. thujona.
Boronia mollis (Soft Boronia) is used as the flora emblem of Katandra due to it prevalence throughout the Sanctuary, however it is considered uncommon in the Sydney area. An erect shrub growing to 1 – 1.5 metres in moist sandstone gullies, it provides an abundance of rich pink flowers in spring, each flower with four petals and 8 anthers. The branches and leaf stalks are densely covered in soft stellate hairs, hence its common name. The leaves are pinnate with 5 to 9 leaflets, the terminal leaflet slightly longer and narrower than the lateral ones. When crushed, the leaves of Boronia mollis have a strong lemon-bitumen odour.