Yes, there are olive trees that do not produce olives or fruit. While most olive trees are grown for their edible fruit and oil, there are some varieties that are purely ornamental and do not yield any olives.
Why do some olive trees not produce fruit?
There are a few reasons why certain olive tree varieties do not bear fruit:
- They are sterile cultivars – These olive trees have been specially bred to focus their energy and resources on foliage and tree growth rather than fruit production. This makes them ideal ornamental specimens.
- They are juvenile trees – Young olive trees generally do not produce fruit for the first 3-5 years. So newly planted trees will be non-fruiting until they reach maturity.
- Environmental factors – Extreme weather, poor soil conditions, improper pruning, and insufficient sunlight can all inhibit an olive tree from setting fruit.
- No pollination – Olive trees are self-fertile but still require pollen transfer for fruit set. Isolated trees with no pollinators nearby will not bear olives.
- Disease/pests – Diseases like verticillium wilt and pests like olive fruit fly can prevent trees from producing olives.
What are some common non-fruiting olive tree varieties?
Some popular ornamental olive trees that do not yield edible olives include:
- Arbequina – A highly ornamental dwarf olive cultivar from Spain. Features silvery green foliage.
- Wilsonii – Native to China and treasured for its distinctive gray-green leaves. Slow growing.
- Swan Hill – Prized for its weeping habit and graceful canopy. Needs warm climates.
- Frantoio – Traditional Italian olive variety grown primarily for its dramatic twisted shape.
- Leccino – Hardy Italian cultivar that makes an attractive compact ornamental tree.
Where are non-fruiting olive trees used?
Non-fruiting olive trees are commonly used in the following locations and contexts:
- Bonsai culture – Dwarf fruitless olive varieties are popularly shaped into bonsai specimens.
- Containers/pots – The compact root structure of many sterile olive cultivars makes them ideal for potted environments.
- Mediterranean gardens – Olive trees are a distinctive part of Mediterranean landscape design and aesthetics.
- Screening – The dense foliage and evergreen habit of olive trees can be used for privacy screens and windbreaks.
- Topiaries – Olive trees can be pruned into ornamental shapes, spirals, and standards.
- Urban landscapes – Sterile olive trees are useful in downtown areas where fallen olives would be messy.
- Specimen planting – Olive trees make striking stand-alone focal points and statement trees in gardens.
What care do non-fruiting olive trees need?
Ornamental olive trees have similar care needs as fruiting varieties:
- Full sun – Olive trees require at least 6 hours of direct sunlight daily for good growth.
- Well-drained soil – They are intolerant of wet, soggy soils and need good drainage.
- Moderate water – Water regularly to establish, then reduce once established. Drought tolerant when mature.
- warmth – Most cultivars only thrive in USDA zones 8-10 without winter protection.
- Shelter from wind – Olive trees benefit from a sheltered location away from intense winds.
- Occasional pruning – Remove dead/damaged branches to encourage healthy growth.
- Nutrient support – Apply a general purpose or citrus fertilizer in spring and fall.
Are there any benefits to growing olive trees solely as ornamentals?
Some potential benefits of growing non-fruiting olive trees include:
- No messy fruit drop – Sterile varieties will not produce messy, staining olives.
- Neat form – Without the weight of fruit, ornamental olives often have a tidier, dense branch structure.
- Blooms – Olive blossoms on fruitless varieties can be abundant in spring.
- Evergreen leaves – Olive foliage adds year-round color and texture.
- Hardiness – Many oleanders withstand heat, drought, pests, and diseases well.
- Long lifespan – Olives are long-lived trees, with lifespans over 200 years in ideal conditions.
- Sanitation – Removing fallen olives can be time consuming and attracts wasps.
Overall, non-fruiting olives make excellent low maintenance landscape trees while avoiding the potential hassles of olive harvests. Their cleanliness and hardiness make them ideal for urban locations and warm climates.
What are some common pests and diseases?
Some pests and diseases that may impact ornamental olive trees include:
- Olive fruit fly – While they don’t damage the tree, fruit flies will emerge from fallen olive fruits.
- Scales – Soft and armored scale insects can infest twigs, leaves, and branches.
- Olive knot – Caused by a bacterium, this disease creates abnormal growths on stems and twigs.
- Anthracnose – A fungal disease that causes leaf spots, twig dieback, and fruit rot.
- Verticillium wilt – Fungal soil-borne disease that causes wilting, defoliation, and death.
- Peacock spot – Fungal disease creating olive leaf spots and early defoliation.
- Olive leaf spot – Bacterial infection leading to defoliation and reduced vigor.
Practice sanitation, avoid overwatering, use preventative fungicides/insecticides when needed, and prune out infected wood to help manage diseases.
What are some cold-hardy olive tree varieties?
Some olive cultivars that can tolerate colder winter temperatures include:
- Arbequina – One of the most cold hardy olives, tolerating temperatures down to 10°F when mature.
- Kalamata – Greek olive variety hardy to about 15°F. Produces table olives.
- Picholine – Withstands temperatures up to 10°F. Produces olives for oil.
- Ascolano – Survives temperatures as low as 10-15°F. Large table olive cultivar.
- Barnea – Israeli variety hardy to 15°F. Widely adapted and high yielding.
- Koroneiki – Moderately cold hardy to around 15°F. Mainly grown for oil.
- Mission – Traditional California olive tolerating temperatures down to 15°F.
- Manzanillo – Withstands cold to 10°F. Widely grown for table olives.
Even cold hardy olive varieties will benefit from protective winter mulching in cooler climates.
Are olive trees able to survive and grow in containers?
Yes, many olive trees are well-suited to container growing. Dwarf and compact ornamental olive varieties in particular adapt well to pots and containers. Some tips for container growing olives include:
- Choose a dwarf or semi-dwarf cultivar suited to containers. Arbequina, Wilsonii, and Leccino are good options.
- Use a large pot, minimum 15-25 gallons, and make sure it has drainage holes.
- Use a quality potting soil designed for container plants.
- Water regularly to keep soil moist but not saturated.
- Fertilize in spring and summer with a complete liquid feed.
- Provide as much sunlight as possible.
- Shelter potted trees from intense winter winds.
- Renew potting mix and prune roots/foliage to maintain plant health.
With the right olive variety and proper care, container grown olive trees can thrive for many years in patio pots or other compact spaces.
Can you successfully grow olive trees indoors?
Growing olive trees indoors is challenging but possible with the right conditions. Here are some tips for growing olives as houseplants:
- Select a dwarf cultivar like Arbequina that can be maintained small through pruning.
- Provide a very large pot, at least 15-25 gallons, to accommodate the tree’s extensive root system.
- Choose a fast-draining indoor potting mix amended with perlite for aeration.
- Situate the plant in the sunniest indoor location possible – south or west facing windows are ideal.
- Supplement natural light with at least 14-16 hours of daily grow lights during fall and winter.
- Maintain warm temperatures between 65-80°F year-round.
- Water thoroughly when soil surface is partly dry. Avoid saturated soil.
- Fertilize monthly during the growing season with indoor plant feed.
- Prune as needed to restrict size and promote compact growth habit.
With the right conditions, miniature olive trees can make interesting and unusual houseplants.
What are some dwarf olive tree cultivars suited for small gardens?
Some excellent dwarf olive cultivars for small space gardening include:
- Arbequina – Very compact Spanish variety growing only up to 8-15 feet.
- Frantoio – Traditional Italian dwarf cultivar reaching 8-12 feet at maturity.
- Leccino – Hardy dwarf tree well-suited to containers. Grows to 6-10 feet.
- Little Ollie – Ultra compact hybrid variety growing just 4-6 feet tall and wide.
- Wilsonii – Ornamental Chinese olive staying under 10 feet. Gray-green leaves.
- Sevillano – Moderately dwarfing olive that produces a heavy olive crop. Reaches 10-15 feet.
- Kalamata – Compact Greek olive renowned for flavorful table olives. Grows 10-15 feet.
With their modest size and productive nature, dwarf cultivars allow gardeners to enjoy olives even in cramped growing areas.
What are some ways to control the size of olive trees?
Some techniques to restrict olive tree size include:
- Planting a dwarf cultivar suited to available space.
- Growing in containers or pots to limit root spread.
- Summer pruning to reduce shoot growth and stimulate fruiting.
- Thinning cuts to remove inward growing branches and improve air circulation.
- Maintain a compact shape through regular pruning every 1-2 years.
- Head back long branches by a few feet to encourage branching nearer the trunk.
- Remove suckers and watersprouts that sprout from the the trunk or roots.
- Pinch or clip back the central leader on young trees to promote bushiness.
With regular pruning and care, the size of standard olive trees can also be restricted enough for smaller residential properties.
What are some cold hardy substitutes for olive trees?
Some possible cold climate substitutes for olive trees include:
- Russian olive (Elaeagnus angustifolia) – Hardy, silvery foliage and edible fruits. Withstands -25°F temperatures.
- Autumn olive (Elaeagnus umbellata) – Fragrant spring blooms and bright red berries in fall. Hardy to -20°F.
- Glossy privet (Ligustrum lucidum) – Evergreen shrub/small tree with olive-like leaves. Tolerates -10°F when established.
- Southern wax myrtle (Myrica cerifera) – Retains evergreen foliage in milder winters. Hardy to 0°F.
- American arborvitae (Thuja occidentalis) – Grows in a dense columnar form like Italian cypress. Withstands -30°F.
- Japanese umbrella pine (Sciadopitys verticillata) – Conical evergreen conifer suited to containers. Hardy to -25°F.
Certain olive varieties like Arbequina and Mission can tolerate temperatures down to 10°F when mature, making them options for warmer parts of colder climates.
Conclusion
While most olive trees are grown for their edible fruits and oil, there are ornamental varieties that produce no olives at all. These non-fruiting olive cultivars offer attractive foliage and growth habits without the mess and hassle of olive harvests. Sterile olive varieties require similar care to fruiting types but avoid problems with fallen olives. With an abundance of elegant evergreen foliage and architectural shapes, fruitless olive trees are ideal for gardens, containers, and landscaping in warmer regions.
