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How to Divide Lomandras: An Expert’s Step-by-Step Guide

The genus Lomandra has become a staple among experienced home gardeners and professional landscapers alike. Renowned for their hardiness and adaptability, lomandras are perennial shrubby, grass-like plants that are native to Australia.

Their popularity stems from the plant’s ability to thrive in various climates and soils, making it a versatile choice for both private gardens and public landscapes. Whatever size your garden is, there’s a species or cultivar that’s perfect for your space.

One of the many advantages of growing lomandras is their ability to be divided into separate clumps, allowing for easy propagation when done correctly. This is a simple process of digging up a healthy plant and splitting it into two or more parts, each with a section of the stem (rhizome) and root system intact.

Dividing your lomandras not only allows you to multiply your plants for free but also revitalises older plants and promotes healthier growth.

It’s important to note that plants with plant breeder’s rights (PBR) cannot be propagated if they are to be sold. They can only be propagated for personal use. Nurseries grow these using specialist methods, often from tissue culture, and it’s sometimes easier or more cost effective based on your time to buy them. However if you have the time, and are not selling them, it maybe worthwhile doing it yourself.

You could get several new lomandras out of this single clump. Image source: Daniel Fuller

When to Divide Lomandras

Late winter or early spring is usually the best time to divide lomandras as this allows for maximum recovery and growth. This way, they’re ready to grow new roots in time for the growing season. Too early, and your baby clones (or “pups”) will have to live on the reserve energy in their existing stems (or “rhizomes”) and roots. Too late and they’ll have to battle hot weather while adapting to their new growing environment.

With that being said, if you need to divide them at the “wrong” time, they’re probably able to tolerate it. Especially if there are plenty of healthy rhizomes and roots to live off until they’re able to grow a decent root system.
That’s why it’s recommended to irrigate plants a few days prior to dividing, and to take a big enough sample of rhizome and roots when doing so.

Preparing for Division

Before diving into the division process, it’s important to prepare adequately. This involves selecting suitable plants, ensuring their vitality, gathering the necessary tools, and preparing the planting area. It’s also crucial to ensure that the selected lomandras are healthy and mature enough for division.

A Step-by-Step Guide to Dividing Lomandras

In this section, we’ll provide a detailed, step-by-step guide on how to divide lomandras properly.

  1. Selection: Choose a healthy, mature lomandra plant for division. The plant should ideally be a few years old and well-established. Select a rhizome with lots of nodes where old leaves used to be, ideally with plenty of roots as well. Ensure it’s well watered, or even better, give it a drink of seaweed solution a few days prior to dividing.
  2. Pruning: Before removing the plant from the ground, trim back the leaves to about one-third of their original length. This reduces stress on the plant and helps it recover more quickly after division.
  3. Digging Up: Carefully dig up the chosen clump, ensuring that you include enough rhizomes and roots to support each divided section. Be gentle and avoid damaging the root system of the mother plant as much as possible.
  4. Division: Use a sharp knife, a trowel, shovel or old hand pruners to divide the root ball into smaller sections. Each section should have a good amount of roots and foliage as discussed.
  5. Planting: Plant each division in a well-prepared soil, ensuring that the planting area is well-drained and rich in organic matter. You can plant the rhizome and roots in the soil, but keep all leaves above the soil surface. Water the new plants thoroughly after planting and continue to provide regular water until they’re established.
  6. Care After Division: Keep an eye on the newly divided plants, providing extra water and care as needed. It may take several weeks for the plants to become fully established. You can feed the “new” plants with a seaweed solution, which is more of a health tonic than a true fertiliser, but avoid fertilising with a high NPK ratio until new growth has occurred.

Common Mistakes to Avoid When Dividing Lomandras

Finally, we’ll highlight some common errors that gardeners might make when dividing lomandras and provide solutions to avoid them. By being aware of potential pitfalls, you can ensure a successful division process and enjoy the benefits of additional lomandras in your garden or landscape.

  1. Insufficient Understanding of Lomandra Growth Habits: As perennials with a clumping habit and robust root systems, lomandras can withstand division. However, it’s important to understand their biology, meaning the different plant parts from roots to shoots, and their abilities and needs. Strappy plants like lomandras have different needs compared with trees, woody shrubs, and annual plants.
  2. Inadequate Plant Material: When dividing lomandras, each section must have enough plant material to establish. Neglecting to ensure this can lead to unsuccessful propagation. The most common reason for failure to establish is an inadequate amount of rhizome; these plants can often establish without a lot of roots on the pup as long as there’s enough stem. Even so, it’s always best for each pup to have a decent root system. It’s even better when the roots are encased in the original soil you’ve dug up.
  3. Incorrect Timing: Dividing lomandras is best done in late winter or early spring, allowing the plant enough time to establish its roots before the heat of summer. Dividing at the wrong time could stress the plants and hinder their growth. That’s not to say it might not succeed long-term if you divide at the “wrong” time of year, though.
  4. Overwatering or Underwatering: After division, lomandras need sufficient watering to help them establish. However, they don’t love soggy conditions before they establish, so keep the soil moist but not wet for long periods. A good rule of thumb is to keep the soil moist without being wet.
  5. Not Trimming Back Leaves: It’s recommended to cut back the top growth quite significantly when dividing lomandras. This prevents losing excess water to transpiration and helps the plant focus its energy on establishing roots.

By avoiding these common mistakes, you can ensure the successful division and growth of your Lomandras.

These lomandras are looking their absolute best. You could take a few pups from a plant this well-established, but you certainly don’t need to thin or prune them yet! Tanika® Lomandra longifolia ‘LM300’ PBR.

Daniel’s Wrap

Dividing lomandras can be a rewarding task for both experienced home gardeners and professional landscape maintenance experts. Not only does dividing plants allow you to thin out overgrown patches of your garden, but it gives you a free source of “new” plants that you can install in other parts of your garden.

Understanding the basic biology of lomandras, knowing the best time to divide them, preparing adequately for the process, and following the step-by-step guide above will ensure a successful division. Keep in mind the common mistakes to avoid and remember, patience is a virtue.

So, embrace this task with confidence, and enjoy the multitude of benefits it can bring to your garden. The key to successful gardening lies in understanding and working with nature, and dividing your lomandras is a perfect example of this. Enjoy the process!

Daniel is a writer and content creator for Ozbreed, one of Australia's leading native and exotic plant breeders.

Daniel has worked in various capacities within the horticulture industry. His roles have ranged from team leader at several companies, to creator of the Plants Grow Here podcast and Hort People job board, as well as his position on the National Council for the Australian Institute of Horticulture (AIH).

He's passionate about explaining how to care for different types of plants to ensure home gardeners and professional horticulturists alike can get the most out of the plant babies.

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