How to Grow Eureka Lemon Trees

Eureka lemon trees produce an abundant crop of fruit throughout the year making an attractive addition to the garden. The foliage on an established tree turns from a bronze shade to a bright green and the white blooms are fragrant, pretty, and have a purple-tinged bud. They can be planted throughout the year in warm climates and reach maturity within three years. If you plan to overwinter them indoors, plant in the spring in a container after any danger of frost has passed. Eureka lemon trees are toxic to animals.

Eureka lemons were developed from a seedling planted in Los Angeles, California in 1858. The tree is non-vigorous and has a spreading, open growth habit. It is nearly thornless, cold-sensitive, and relatively short-lived.

How to Plant Eureka Lemon Trees

When to Plant

Eureka lemon trees prefer to be planted during the spring to avoid cold or hot weather.

Selecting a Planting Site

Lemon trees are particularly sensitive to cold weather conditions. The trees need a warm and sheltered position to thrive.

Because they like a lot of water, it isn't recommended to plant your Eureka lemon tree directly into a flat lawn where the grass could get oversaturated. Build up a wide mound to plant the tree on top of or select a sloped position so it can receive enough water without you having to worry too much about drainage.

Spacing, Depth, and Support

Prepare a hole as deep as the root ball and about twice as wide as the root ball.

Eureka Lemon Tree Care

Light

Access to plenty of sunlight is a must for eureka lemon trees—ideally, at least 10 hours a day. Although they can cope in a partial shade location, they won't produce an abundant harvest, and their growth rate will slow significantly.

Soil

You'll need well-drained soil for your Eureka lemon tree, preferably loamy or sandy soil. They thrive in acidic conditions.

Water

Eureka lemon trees are more water-hungry than the Lisbon variety. Ensuring the soil is kept consistently moist is recommended. In the summer, you may need to water the tree every day.

Don't be tempted to mulch around the tree as this can result in waterlogging. Although these trees like to be kept moist, they can't stand saturated conditions or standing water.

Temperature and Humidity

Well-suited to Mediterranean-style climates, Eureka lemon trees aren't a cold-tolerant species. If temperatures reach as low as 20 degrees Fahrenheit, your tree will likely not survive outside. They also don't cope well with harsh winds and need a sheltered location. When the temperatures drop, container-grown trees should be moved indoors to a warm and sunny spot until the return of warmer temperatures.

If your house is very hot and suffers from dry air, using a humidifier can help to ensure the tree receives enough moisture and remains healthy and fruiting.

Their preference is to be kept in temperatures of around 75 degrees Fahrenheit or above for year-round fruiting, although increased cold hardiness does develop as they mature.

Fertilizer

Heavily fruiting trees like the eureka use up a lot of energy and are always hungry as a result. They appreciate organic matter added to their soil and having a bi-annual feed with fertilizer that is specifically designed for citrus trees.

Pollination

Lemon trees are self-pollinating. One blossom contains both male and female parts to allow self-pollination. To help pollination along, you can sacrifice one blossom and rub its interior on the interior of other blossoms which will transfer pollen to the right areas in the flower. When the sacrificial flower wilts, the pollen is used up.

Eureka Lemon Trees vs. Lisbon Lemon Trees

The juicy, tangy, sour fruit from the Eureka lemon tree (Citrus x limon 'Eureka') is sold commercially around the globe alongside the Lisbon variety. Although similar in look and taste, they do have several distinct differences.

Eureka lemons don't have such a prominent mammilla (protruding nipple), and their skin is more textured. The fruit develops along the outside edges of the branches. Eureka lemon trees don't have the thorns you find on the Lisbon type, but, they aren't quite as cold tolerant, and need to be moved indoors if there's even the slightest sign of frost. Eureka has a spreading growth habit and an open form, while Lisbon lemon trees are more upright and their fruit grows inside the dense canopy of the tree.

It can take at least three years before your tree is fully established and ready to produce a healthy crop. If you spot any random flowering in advance of maturity, it is a good idea to remove them to allow all the energy for supporting appropriate early growth.

This type of lemon tree is known for producing a good crop throughout the year when the conditions are right. For the best flavor, the fruit should remain on the tree until soft to the touch, fully ripened, and ready to use.

How to Grow Eureka Lemon Trees in Pots

A Eureka lemon tree can be grown in a pot, but it's best if the container remains outdoors when it's not being overwintered. It's a great option if you live in a cool climate, or have the right environment for a citrus tree but you only have limited space. It's important to realize that potted lemon trees will have more stress because of their confined root systems and are more vulnerable to cold weather.

Choose a large container of any material that's at least 18-inches in diameter, with multiple drainage holes. Fill with well-draining potting soil. Container plants dry out faster than if they were in the ground and the same holds for potted lemon trees. Water twice a week or daily if the weather is extremely hot and dry.

You must prune a potted tree, and monitor for dead, damaged, or sucker branches. Sucker branches tend to grow from the root next to the tree trunk of younger trees and need to be removed so they don't take nutrients away from the real branches.

Pruning

Because of their open-spreading habit, Eureka lemon trees don't need pruning regularly but trim away diseased, damaged, or overcrowded sections. This can be done at any time of the year.

Over the years, eureka lemon trees can reach up to 20 feet in height. If you want to keep them more compact, prune them more often.

Propagating Eureka Lemon Trees

If you want a clone of your parent Eureka lemon tree, you can propagate root cuttings. Unlike some other citrus varieties, lemon trees are pretty easy to propagate from semi-hardwood cuttings. The key is to select healthy, new growth during the late spring or early summer and cut a section that doesn't have any flowers or fruit on it. Here's how to propagate a lemon tree.

1. With a sterile, sharp cutting tool, take a six-inch cutting, making your cut at a 45-degree angle. The cut should be taken right below where a leaf and stem attach.
2. Use a sharp cutting tool to remove all the leaves except for the top three leaves.
3. Dip the bottom two inches of the cutting in rooting hormone.
4. Fill a pot that's about eight inches with equal amounts of perlite and peat moss, then water thoroughly and evenly before inserting the cutting.
5. Make a two-inch deep hole in the soil with your finger or a pencil and insert the cutting.
6. Put a large clear plastic bag over the plant and close it at the bottom of the pot as best as you can with a twist tie or clip. Make a couple of small half-inch to one-inch slits at the top of the bag to let out condensation.
7. Put the pot in a very warm and very sunny area that reaches about 75 to 90 degrees Fahrenheit.
8. Water lightly to keep the soil damp every three days, and make sure the soil stays well-drained.
9. The cutting will begin to root in about two to three months.

Overwintering

This type of lemon tree is generally best overwintered indoors unless you have particularly mild winters. They are not known for their frost tolerance and they don't take well to the soggy conditions that can be created by mulching.

Make sure you position them in a warm, bright spot if you want a good fruit harvest. Be careful temperatures are not overly hot, though, as those that mimic those of early spring can encourage a more abundant bloom.

Common Pests and Plant Diseases

All lemon trees are tasty to a variety of pests and are afflicted by many diseases. Pests can include whiteflies, rust mites, mealybugs, aphids, and scale. While established adult trees usually can withstand an infestation or two, smaller, more vulnerable trees can be decimated by any one of these issues. Signs of pest issues will typically appear on the undersides of leaves or the fruit.

To control and eliminate pests issues, begin by pruning away any dead, unhealthy, or infected areas of the tree. Treat the plant by spraying it with horticultural oil, like neem oil, diluted significantly, reapplying frequently until all signs of infection have ceased.

The most common diseases include citrus canker bacterial disease, and many different fungus diseases, including anthracnose, sooty mold, root rot, and botrytis rot (gray mold), all of which need to be treated accordingly with fungicides.

Harvesting Eureka Lemons

Harvest only mature fruit. Pick ripe lemons by hand by giving the fruit a slight twist so it releases from the branch. If you must pick green fruit due to cold temperatures or vacation, keep the fruit at room temperature to cure allowing the fruit to slowly become yellow. The pulp of Eureka lemons is greenish-yellow, high in juice content, and very acidic. The fruit usually has nine seeds or fewer.