Swan Hill Olive ® Planting & Maintenance Guide

The Swan Hill Olive ® brings shade, color, texture and elegance to any landscape setting.

Nothing is more critical to the long term survival and vigor of landscape trees than the care and attention given to installation planting practices and post installation irrigation.

Contrary to their lush, luxurious appearance, The Swan Hill Olive ® is as low water use and drought tolerant as many native desert tree species. For centuries European Olives have thrived as a commercial crop in many of the Mediterranean's poorest, low organic matter, gravelly and sandy soils, and flourish with only rainfall as irrigation.

The Swan Hill Olive ®, grown on the Olea europaea cv, "Oblonga" rootstock, is adapted to a wide array of soil conditions and landscape settings. All our specimens, with the exception of some 24" and 36" boxes, are field grown in an alkaline, well drained, sandy loam soil, dug, and sold in banded wooden tree boxes.

Tree Placement

To avoid interference with structures, hardscape elements and under-story plantings, consider the relatively dense shade and height and width of a mature Swan Hill Olive®. Careful placement allows for the development of the full, symmetrical canopy and graceful grayish trunks that make the Swan Hill Olive® the focal point of any landscape. Appreciate that the welcome shade generated may reduce the flowering of under-story plantings and thin most grass species.

Planting

No tree, including The Swan Hill Olive®, should ever be planted deeper than the original depth in the growing field. It is preferable to plant the tree as much as 6" above grade as a hedge against any subsidence that may occur over time. The square outline of the boxed root ball should be visible after the tree has been planted, backfill compacted, watered in and the area graded. The planting hole should be no deeper than necessary to keep the crown of the tree 6" above grade.

Do not dig overly deep planting holes and keep
the crown of the tree 6' above grade.

Do not dig overly deep planting holes as this practice lead to subsidence and trees ultimately being planted too deep. Leaving the bottom of the hole largely undisturbed prevents problems associates with poor compaction and settling of the tree over time once irrigation water wets loose soil. Settling of bottom backfill, in partially compacted soil, can also lead to formation of air pockets that prevent effective rooting which is essential for tree stability and long term growth.

The table below lists planting depths, height, width, caliper and weights for individual box sizes. Planting depth measurements reflect our recommendation that Swan Hill Olive® be planted with the box bottoms left in tact.

¹ Planting depth should leave the tree crown at about 6" above finished grade.

² Digging the widest hole possible will encourage lateral root development.

³ Tree weight (lbs) listed are estimates and may vary.

Lower the tree into the planting hole using equipment and manpower appropriate to the task. Swan Hill Olives® are field dug and they are heavier than typical mulch grown trees. Boxes 42" and larger should be lowered into planting holes using a crane and nylon straps. To protect the trunks, rootball and installers, do not remove any banding, bracing or the box bottom, prior to installation. The intact bottom boards will help stabilize the root ball and prevent the tree from settling below the desired planting depth.

Once the tree has been placed in the planting hole and properly orientated, the bracing and bands can be removed.

Backfill around the box with native soil and tamp. Remove box sides by rocking them back and forth. Only two of the four corners of the box are nailed to facilitate removal. Add the balance of the backfill tamp and water at a slow rate to help settle and compact soil. Back fill should only consist of native soil or sand amended native soil. Never add any organic matter to the back fill. Never place gas impervious mulches such as plastic or thick fibrous matted material or sod within six feet of the root ball. A light surface mulch can be incorporated in the top 4" to 6" once back filling, water settling and final grade are established.

Irrigation

Water management in the first 90 days post installation, particularly in the cooler seasons, is very important. Planting in areas where sod has recently been laid or established turf that has been over-seeded present special water management challenges for newly planted Swan Hill Olives®. Do not lay sod within the drip line of the tree. Where possible, avoid planting ground covers, or other installations that will require or lead to the accumulation of standing water or highly saturated soil conditions. The Swan Hill Olives® may not be well suited for planting in flood water retention basins or poorly draining soil depressions.

Give the Swan Hill Olive® at least six months after installation to acclimate before risking over irrigation. This is especially important with Northern California winter time plantings and in the desert areas where night time temperatures regularly approach freezing.

Initial irrigations should be directed towards keeping the transplanted soil root ball moist. If the trees are to be immediately placed on drip irrigation, make sure at least one emitter is near the base of the trunk(s). Where possible flood or basin irrigate transplanted trees for the first couple of irrigations to promote backfill settling and compaction. The frequency and duration of irrigations for a specific time of year will be heavily influenced by a variety of local environmental factors (soil type, season of the year, high winds, water drainage from other areas of the landscape, stage of growth of the tree). It is nearly impossible and highly imprudent to make overly general recommendations about watering schedules. One of the best ways to evaluate root ball and backfill moisture content is by using a soil probe like the Oakfield Soil Sampling Probe. Always angle the probe through the back fill area to penetrate the lower portion of the root ball. Soil samples that can be molded in the hand and retain their shape with slight crumbling are ideal. Irrigation should be delayed if any samples are "muddy" or water can be squeezed from the sample. Moisture levels should be checked at least once a week for the first 6 weeks after planting.

Tree wells, even if only temporary, can simplify post installation irrigation and concentrate water where it is needed.

Testing for soil water penetration and percolation rate can be roughly determined by filling a freshly dug hole with water. Once the pit has drained, refill with water and see how long it takes for the water to move into the soil. If the planting hole fails to drain completely within 24 hours, consider measures for improving drainage.

Fertilizer

One year after planting make annual placements of 10—20 Agriform (21 gram) tablets. Another option is one pound of a balanced fertilizer with slow release nitrogen, micronutrient laced fertilizer such as Osmocote® or Apex®, applied 6-12" deep in 3" holes around the original root ball perimeter. For best results, make applications in September or October. For larger trees make 3 applications, 2 lb each, of a balanced (N,P,K) 10% nitrogen based lawn or citrus fertilizer and distribute applications from late spring to early fall (May to September). All fertilizer applications should be followed by a slow deep watering with a minimum of 15 to 25 gallons of water.

Always consult the directions and applications rates printed on the label of the fertilizer you choose. The label will offer the manufacturers recommended application rates and frequencies and any special local or regional information about the products safe and effective use.

Pruning and Shaping

Swan Hill Olives® should be pruned and shaped at least once and preferably twice a year. Prune in late summer and late winter. Start cleaning out from the interior by removing the dead, shaded or marginally leafed branches. Tip prune limbs only to force growth into empty areas and to maintain symmetry and fullness. Remove all growth or suckers from the base of the tree every year.

Content © Swan Hill Nurseries, LLC
Swan Hill Nurseries, LLC    P.O. Box 420    Waddell, AZ 85355
Email: info@swanhill.com    Phone: 623-935-0545