Chapter 94 Ficus spp.
##Tropical figs
A banyan style ficus in the National Arboretum collection. Link to original image.
Three species of tropical figs are used for bonsai or as indoor houseplants in temperate areas. The fourth is a vining accent plant.
| Species | Common Name | Characteristics |
|---|---|---|
| F. benjamina | Weeping ficus | The most common ficus. There are both full-size and dwarf-leaved cultivars. |
| F. microcarpa | Chinese banyan ficus | The species with the darkest, thickest, most leathery leaves. Cultivars include striped bark forms |
| F. salicifolia | Willow leaf ficus | Long thin leaves produce an airy silhouette. |
| F. pumila | Creeping ficus | A trailing vine with tiny leaves. Small seedlings can be used for accents or saikei. Large trunks can form through fusion of multiple parallel vines |
94.1 Soil: Rich Mix
Ratio: 4 parts bark, 1 part coir, 1 part grit
Add-ins: dolomitic limestone (~5 lbs/yd), Tree-Tone (15 lbs/yd)
pH: ~6.5 (slightly below neutral)
Moisture: moisture retaining. Ficus do best if allowed to dry out slightly between waterings.
94.2 Light
Routine: Full or partial sun, but indoors they prefer a bright spot without direct sun. Avoid sudden changes in light, especially for F. benjamina, which is prone to dropping leaves when the light level changes too much.
ALL ficus will sun scorch if they are moved from indoors to outdoors too quickly. Give them several days with increasing exposure (starting with just 20 minutes or so) to adapt before leaving them in open sun unprotected.
Summer: Mid-day shade or filtered lighthelps prevent leaf scorching.
A forest slab planting of Ficus retusa soaking up late day sun. Link to original image.
94.3 Cultivation Notes
94.3.1 Potting & Root Pruning
I check all of my ficus each spring, usually just before I bring them outdoors. I try pushing the trunks to one side, and if the entire block of soil moves as a unit, I tag the tree for repotting. If possible I give them a couple weeks of outdoor acclimation before repotting, but if they are pushing a lot of new growth, I usually repot as soon as possible.
Ficus tolerates root pruning well. I regularly take 25-30% of the roots off when repotting, and have removed up to half of the roots from a large, healthy tree. The roots can be a little brittle, so be patient and work slowly when untangling larger roots. Dunking the root ball for 10 minutes in warm water seems to help.
Do not be surprised if a newly repotted tree stops growing and sulks for a few weeks. I’ve had it happen fairly often, for no obvious reasons. It does not consistently happen to the same trees either. Some trees sulk after repotting one year, then do fine the next time.
94.3.1.1 Top & Branch Management
Heavy pruning: remove large branches in winter, or when trees are dormant. Cuts will bleed latex sap. Try to use slightly blunt tools for pruning a ficus; ragged edges actually bleed less than cuts from sharp blades.
Fine pruning: clip shoots with 6-8 leaves back to 1-2 leaves. Some stylists have good luck with clipping small branches back to bare wood, but in my experience, branches are just as likely to die back instead.
Leaf pruning: others say you can leaf prune ficus, but I have never had any luck with reducing the leaf size.
94.3.2 Feeding
Ficus trees are not fussy about fertilizer ratio. They do well with any slow release shrub and tree fertilizer, applied at half the recommended rate, or water soluble fertilizer made up at half strength rather than full strength.
They feed heavily in the growing season, so can be fertilized weekly if using soluble fertilizer.
94.3.3 Pests & Problems
I have not had pests on trees that spend their summer outdoors. Trees that remain indoors all year can become infested with scale, aphids, or whiteflies.
Chemical Warnings Ficus are sensitive to many chemical pesticides. Try to control pests with insecticidal soap first, and test all chemicals on a sacrificial branch before spraying an entire tree.
94.3.4 Winter Storage
Ficus are natives of the tropics, and do not like to be outdoors if the temperature is consistently below 45oF. They cannot stay outdoors in winter here; move them into a brightly lit area indoors in mid-fall, and do not take them back outdoors until nighttime temperatures stay above 50oF. They thrive in our summer heat and humidity, but need to be watered regularly if there is not consistent rainfall.
94.4 Propagation Notes
I have had good luck rooting large woody branches up to an inch in diameter. Dip clipped branches in rooting hormone and sink in a 1:1 mix of sharp sand or perlite and moist sphagnum peat. They need to be kept in high humidity for several weeks while roots develop.
94.5 Artistic & Styling Notes
A young ficus forest planting (top) and a more mature forest grouping. The younger planting still has clearly separate surface roots, and slightly darker, more brown immature bark. The older planting has intertwined foliage, larger nebari with fused roots, and pale ash-gray mature bark. Link to original image 1; image 2.
Ficus stems and roots fuse together easily, so gaps in the nebari can be filled by planting rooted cuttings from the tree near the gap, bending them in, and tacking the cuttings in place.