Tropical evergreen climbing plants which are grown for their ornamental foliage. They are natives of South America and belong to the family Sapindaceae. P. thalictrifolia, the principal kind, grows 20 ft. high and has twining stems clothed with finely divided leaves resembling those of Thalictrum. The leaves are bronze-pink when young and change to green as they mature. The small pinkish flowers are inconspicuous. The name Paullinia commemorates Simon Paulli, a professor of
botany at Copenhagen during the 17th century.
Foliage Plants for the Greenhouse. Paullinias require a minimum winter temperature of 55 degrees and a soil compost of equal parts of loam and leaf mold or peat moss with sand added freely.
The plants are grown in large pots or in a bed of soil in the greenhouse and the shoots are trained to wires or a trellis fixed to the roof. They should be set in their permanent locations in March.
Well-rooted plants in 5-in. pots are the most suitable for planting. The pots to which they are permanently transplanted should be at least 12 in. in diameter and filled to one fifth of their capacity with crocks, these being covered with a layer of rough leaves. Sufficient soil is added to bring the top of the ball of roots 2 in. below the rim of the pot. The plant is then knocked out of its old pot, and the crocks and loose soil are removed from the roots before the plant is set in the large pot. Next, soil is filled in and made firm, a 1-in. space being left at the top for watering.
To prepare a bed for planting, the soil is taken out to a depth of 18-30 in., and a 6-in. layer of broken bricks is placed in the bottom. These are covered with pieces of leaves or turf to prevent the soil from washing into the drainage, and the remainder of the hole is filled with good soil.
After a few days a hole is taken out sufficiently wide to allow the roots to spread out to their fullest extent, and deep enough for the ball of soil to be covered to a depth of 1 in.
After planting or potting, the soil is well watered and the plants are shaded from sunlight. When they are established, the soil is kept moist throughout the summer, and the plants are exposed to full light to develop a bronze-pink tint in the leaves.
Summer and Winter Care. A moist atmosphere must be maintained by frequently damping the floor and benches, and the foliage should be sprayed twice a day in summer. Less atmospheric moisture is required in winter, and in this season the soil is only watered when it becomes almost dry.
Instead of training the shoots to wires fixed to the greenhouse roof, you may grow the plants in pots and train the shoots to a tripod of stakes fixed in the pot. If the shoots are regularly pinched, a compact pyramid of greenery will be formed.
Pruning consists of cutting back extra-long shoots in February.
Propagation Is by Cuttings. Shoots 2 in. in length are taken off in spring. The leaves from the lower half of the shoot are removed and a cut is made just below the bottom joint. The shoots are then inserted in a propagating case with a bottom heat of 65-70 degrees. Each morning the top of the case should be raised to change the air, and the surplus moisture must be wiped from the underside of the glass.
When roots have formed, the plants are potted separately in 3-in. pots and later on in 5-in. pots, from which they are planted out or set in the large permanent pots.