The LSU Purple fig tree, developed by the Louisiana State University Agricultural Center, offers home gardeners a reliable source of sweet, high-quality fruit. This self-fertile cultivar is known for its manageable size and its ability to produce figs with a closed eye, which helps resist spoiling from pests and moisture. The tree’s upright growth habit and heat tolerance make it well-suited for many climates, thriving in USDA hardiness zones 7 through 10. This guide provides the steps for establishing, maintaining, and harvesting the fruit of the Ficus carica ‘LSU Purple’.
Establishing the LSU Purple Fig
Successful establishment begins with selecting a location that receives full sun, ideally a minimum of six to eight hours of direct sunlight daily. The LSU Purple fig tree performs best in well-draining soil that is rich in organic matter, with a slightly acidic to neutral pH range between 6.0 and 7.0. If your native soil is heavy clay, amending it with compost or planting in a raised bed will improve drainage, as the tree will not tolerate standing water.
When planting in the ground, space trees at least 10 feet apart to ensure adequate air circulation and room for the mature spread. Plant the tree slightly deeper than it was in its nursery container, but avoid amending the backfill soil with fertilizer at the time of planting. For colder climates or restricted spaces, the LSU Purple is an excellent candidate for container planting, requiring a pot at least 24 inches wide and deep to accommodate its root system.
Essential Maintenance: Watering, Feeding, and Pruning
Consistent soil moisture is necessary for the LSU Purple fig, particularly during the tree’s first few years and throughout the fruit development period. Fig trees have shallow, widespread root systems, so deep, infrequent watering is more effective than light surface watering. Aim to provide about one inch of water per week, either through rainfall or irrigation, especially during dry spells, but always allow the soil to dry slightly between applications to prevent oversaturation.
Fertilization should be approached cautiously, as over-fertilizing, especially with high-nitrogen formulas, can lead to excessive leafy growth and reduced fruit yield. A balanced, slow-release fertilizer, such as a 10-10-10 or 8-8-8, applied in late winter or early spring just before new growth begins, is appropriate. For established trees, apply one pound of a balanced formula per year of the tree’s age, up to a maximum of ten pounds for mature trees. Monitor the tree’s annual shoot growth, which should be between 1 and 1.5 feet; if growth is slower, increase the fertilizer application slightly, and if growth is excessive, reduce it.
Pruning is best performed during the dormant season in late winter or early spring, before the buds swell. Pruning aims to maintain a manageable size, remove any dead or crossing branches, and open the canopy for better light penetration and air circulation. The LSU Purple fig often produces three crops, so light summer pruning to remove growth that blocks sunlight can be performed, but major shaping should be reserved for the dormant period.
Protecting Your Tree from Cold and Pests
The LSU Purple fig thrives across USDA zones 7 through 10 and can tolerate temperatures down to about 10 degrees Fahrenheit. In zone 7, or if extreme cold is forecast, winter protection is required to prevent dieback. In-ground trees can be insulated by applying a thick layer of organic mulch, four to six inches deep, around the root zone, and wrapping the main trunk with burlap or a protective material.
Container-grown figs should be moved to an unheated, insulated space, such as a cool basement or garage, once the leaves drop. While LSU Purple is noted for its above-average resistance to pests and diseases, gardeners should be vigilant for common fig pests like scale insects and spider mites. Good cultural practices, such as maintaining strong air circulation and removing fallen debris, are the first line of defense, and organic treatments like horticultural oil can be used for persistent infestations.
Harvesting the LSU Purple Fig
The LSU Purple fig is highly prolific, producing up to three crops in a single season: a light spring crop, a heavy summer main crop, and a smaller fall crop. The fruit is medium-sized with glossy, dark purple skin and contrasting light strawberry-colored flesh. Ripeness is indicated by a change in color from amber to a deep, uniform purple.
A ripe fig will soften noticeably and hang downward on the branch, often showing a slight crack near the eye. Figs do not ripen further once picked, so they should only be harvested when fully soft to the touch, feeling similar to a ripe avocado. Check the tree daily during the harvest window, which typically runs from July through the first frost, and gently twist the fruit from the branch to avoid damaging the skin or stem.