The Plant Company grows and sells thousands of Karamu (Coprosma robusta) plants throughout NZ. We pride ourselves on producing high quality plants and seeing the joy from our customers when they receive them. Explore our Karamu plants and the expert advice articles which have been produced by experienced gardeners and nurseryman alike. These articles cover key questions about growing Coprosma robusta successfully.
Caring for Coprosma robusta is about making sure the plants are growly strongly. Our plant care articles provide the necessary advice to give you the greatest chance of success. Afterall, there is nothing worse than putting the effort into planting for them to fail. Therefore, follow our advice for Coprosma robusta care and give yourself the best chance of success.
The most important part starts with planting and our article, How To Plant Karamu, provides sound advice on how to do this properly. So, let’s now assume your plant is growing well and you want to keep it that way!
Winter is the perfect time for mulching and trimming your plants. Trimming can be aggressive or subtle as you like. Typically, plants are trimmed to contain growth and encourage fresh, new foliage. Karamu will sprout away again no matter how hard they are cut back and provided the cut stem is healthy.
Organic matter such as compost or sheep pellets should be spread liberally around the plants and then overlaid with a mulch during winter. The Plant Company has three very good options for mulch. The first is coco fibre matting which is made from the husks of coconuts. The second is Earth Mat which is made from recycled paper. Both of these break down to become part of the soil within two years. The third is black plastic matting which will last 20 years or more. Whichever mulch is used, The Plant Company recommend stones, bark chip, or other similar products be spread over top for aesthetic purposes. The Plant Company does not recommend adding fertiliser during winter as this is better applied in spring so less is wasted. However, adding organic matter such as compost is quite okay.
Spring is the perfect time for fertilising the plants as they start to bounce into life. The Plant Company has fertilisers which have been specially blended for different plants and in this instance, our native plant fertiliser will give them the correct boost and keep them fed for 12-months. A suitable alternative is our organic fertiliser which will also keep them well fed but they will require a secondary application in autumn.
Summer is when the plants need regular watering and this should be undertaken every second day on the hottest days. Plants that are establishing need particular attention as their root system will not have penetrated deep enough to secure consistent moisture yet.
Caring for Karamu in autumn is about keeping the plants healthy. Foliar feeding using a liquid fertiliser can be undertaken during spring, summer, and autumn if you have time but this is not essential if solid fertiliser and/or good amounts of organic matter have already been applied. If you think the plants need an extra boost or have some yellowing, however, a liquid fertiliser won’t hurt.
There is a wealth of information about Coprosma robusta and The Plant Company is often asked specific questions which we have laid out in this section.
Ripe Coprosma robusta berries, also commonly known as Karamu berries, are edible. They were traditionally consumed as a food source by Maori people. Make sure the berries are ripe as unripe berries are not tasty. Be sure to identify the plant correctly as there can be look-alikes that are poisonous.
Coprosma robusta, also commonly known as Karamu, can grow to be around 6 metres (20 feet) tall. They are typically considered shrubs, but under the right conditions, they can reach the size of a small tree.
Coprosma lucida and Coprosma robusta, both known as karamu, share some similarities but have distinct features that can help you tell them apart. Here are some of their key differences:
Leaves:
Size and Growth Habit:
Fruit:
Other:
Providing the best fertiliser for [Karamu] is important to ensure the plants perform well. The correct fertiliser depends on whether the plant is grown in a pot or in soil, and getting this wrong can be disastrous for your plants. Our articles provide the best advice about fertiliser for Karamu so you can achieve the amazing results you are after.
Karamu are vigorous plants that require feeding to keep them growing optimally. The Plant Company’s native plant fertiliser has been blended to give plants an initial boost and then sustained nutrition for 12-months. We recommend the fertiliser is applied to the soil surface in spring just as the plants start to grow actively. More importantly, we advise that no fertiliser is placed in the hole at planting, but rather spread around the soil surface so it can wash through the roots as it releases. This ensures that nutrients remain in the soil around the plant rather than being lost through the soil profile to where the plant cannot reach it. This also applies to plants grown on sandy soils. The Plant Company’s native plant fertiliser is therefore very environmentally friendly and longer lasting than most other products in the market.
Foliar feeding using a liquid fertiliser can be undertaken if you have time but this is not essential if native plant fertiliser has been applied. If you think the plants need an extra boost or have some yellowing, however, a liquid fertiliser application won’t hurt. A great benefit of foliar feeding is that it helps keep the leaves strong and lush.
Karamu grown in containers require different fertiliser to those grown outdoors in soil. In this instance the correct fertilisers to use are either the container plant fertiliser or fertiliser tablets. Each of these will provide safe, sustained, and complete nutrition to the plant for the next 12-months. Using other types of fertiliser can be detrimental to the plant and may result in plant injury or death.
Foliar feeding using a liquid fertiliser can be undertaken if you have time but this is not essential if container plant fertiliser or fertiliser tablets have been used. If you think the plant needs an extra boost or has some yellowing, however, a liquid fertiliser application won’t hurt. A great benefit of foliar feeding is that it helps keep the leaves strong and lush as the nutrition is right where the plant needs it.
There is a wealth of information about Karamu trees and The Plant Company is often asked specific questions which we have laid out in this section.
Yes, Karamu berries are edible! They were traditionally consumed as a food source by Maori people. Make sure the berries are ripe as unripe berries are sour and not at all tasty. Identify the plant correctly as there are look-alike plants that produce poisonous berries. Consume them in moderation, especially if you're not familiar with foraged foods.
Ripe karamu berries are not poisonous and are actually a traditional food source for Maori people. Unripe berries are not very tasty and best avoided. Always identify the plant correctly before consuming the berries as there can be poisonous look-alike plants.
Karamu plants, also known as Coprosma robusta, can grow to be around 6 metres (20 feet) tall. They are typically considered shrubs, but under the right conditions, they can reach the size of a small tree. The size of a karamu will depend on the climate, soil conditions, and how much space they have to grow.
Some key features to help you identify Karamu (Coprosma robusta) include:
Karamu itself is the most common name for the plant scientifically known as Coprosma robusta. It's widely recognized by this name in New Zealand, particularly among Maori communities who have used it for generations.
Karamu is a versatile plant that has long history of uses among the Maori people in New Zealand:
The Karabu tree is the incorrect spelling for the Karamu tree. This is a small, NZ native tree, that features lush green foliage and orange berries.
The Plant Company have produced this series of articles to provide advice for trimming Karamu plants so you can manicure your bushes with confidence and success.
Coprosma robusta, also known as Karamu, is an excellent choice for a hedge. It can grow up to 75 cm per year and produces a dense screen quickly. The small leaves are held on a tight network of branches on this evergreen, which collectively makes it perfect for creating privacy in a garden or at the front of a property. Karamu can also be pruned to any height or shape, which makes it suitable for both formal and informal hedges. Once Coprosma robusta becomes established, the plants become low maintenance as they are largely drought tolerant and disease resistant. Finally, the glossy green leaves and bright orange berries in late summer and early autumn, not only add visual interest, but will attract birds into the garden. Considering all these points, Coprosma robusta is an excellent choice for a hedge.
Karamu are trimmed each winter to contain growth and encourage fresh, new growth. The Plant Company recommends they are lightly trimmed each year to the size you are after and allowing for 30-50 cm of extension growth. You can be as aggressive as you want as the plants will sprout new buds from healthy stumps. Any dead stems should also be removed at this time, along with stems that show disease.
A mistake often made is to not prune the plants hard enough. This error generally results in a woodier plant and a much larger plant that can be difficult to contain. Karamu are very forgiving plants and even if you get the trimming wrong, they will recover!
Karamu can be trimmed at any time of the year, though winter is the time recommended by The Plant Company. It is the new growth that makes the plants look amazing, so cutting out the older growth to make way for the new growth in spring is the goal. All you need is a good pair of secateurs and you can be as aggressive as you want. The plants will sprout new buds from stumps as long as they are not diseased. When Karamu are grown in pots, they are often clipped every 2-3 months. This keeps them dense and helps make them shapelier.
Planting Karamu and getting them to grow well is generally easy when you get a few of the basics right. This involves planting them in the right soil type, choosing the most ideal planting position, and ensuring the plants have the essentials to thrive. The Plant Company has the right advice to ensure success when you are growing Karamu.
The answer to this question depends on how much shade. As shade levels increase, Karamu tend to become “leggy” and more open in their growth habit. In full sun they tend to be much more compact in their growth. So yes, they will grow in partial shaded conditions such as down the side of a house or under dappled light from a tree, but growth is likely to be less than if they were growing in better light. Please note that in partially shaded environments the central leaves on the plant will often yellow and fall which can result in a plant that has mostly exterior foliage only.
Karamu make amazing hedges (both formal and informal) and to create an outstanding hedge The Plant Company recommends spacing them 50-70 cm apart. The faster you want the hedge to fill in, the closer they should be planted is the general rule. With this planting regime they will close in quickly and also push each other upwards as they compete for light. The result is a fabulous hedge every time.
You can go out to 1 m if the budget is tight but that will often result in a gap at the bottom between plants which is hard to fill. The gap results from the natural vase shape with which these plants grow. In this situation, opt for smaller grade sizes and plant more of them rather than going with bigger plants as this will make the money go further and produce a better result in the longer term.
Karamu are generally vigorous and establish quickly. Most will grow about 1 m or more per year provided they are at least 30 cm tall when planted. Planting shorter plants will typically only give 4-50 cm of growth in the first year.
Choose a full sun position with good drainage for your Karamu plant. The hole should be dug at least 50-75% deeper and wider than the container the plant is currently growing in. A planting spade makes the hole digging a lot easier. The Plant Company recommends incorporating compost or sheep pellets into the soil to provide additional organic material, but this is not essential. Do not put fertiliser in the bottom of the hole, rather spread that on the soil surface after planting, and preferably do this when the plant is actively growing in spring.
Remove the plant from the container it is growing in by either pulling it free or by cutting the bag. We recommend cutting the bag or container, especially for larger grade plants, to minimise any chance of damaging the roots. If the roots have been growing in a circle or are all bound up you can tease them apart if you want but this is not essential. Similarly, you don’t need to remove any of the growing media. The Plant Company does not recommend cutting the roots, even if the plant is root-bound as this offers no benefit. This is explained in our article, Managing Rootbound Plants.
Now place the plant in the hole and make sure it is level with the soil surface before filling in around it. If it is above the soil surface, dig more out. If it is below, put in more soil and retest the level. Once the plant is set level with the soil surface, add more soil gradually and firm it around the plant using gentle pressure as you go. Scatter native plant fertiliser across the soil surface after planting and the give the plant a good watering.
Karamu are best planted from mid-autumn until late spring. During this time, they can cope with the stresses associated with planting (root damage mainly) more easily than if they have to also cope with heat and moisture stress as well. They can be planted in summer provided they are well-watered and the roots have plenty of growing media attached when planted. If watering is a challenge, The Plant Company advises planting from late-autumn through until early-spring. Make sure you have a good planting spade to make this job a lot easier.
A full sun or partial shade position with good drainage is essential for getting the best results with Karamu. On poorly drained sites or with over-watering they tend to become stunted and sickly looking with leaves dropping. This can also cause and result in root rot issues that may eventually kill the plant if drainage is very poor.
As shade levels increase, Karamu tend to become “leggy” and more open in their growth habit. In full sun they tend to be more compact and denser which is particularly important if you are considering a hedge. The shaded option is more for standalone plants where density is less important. The position should also be moderately sheltered so fresh growth is not damaged by wind and this will help produce a better shaped plant overall. This is not essential as they can cope with some wind. Where ever they are grown, make sure they have plenty of room to expand!
Whether you need assistance finding the plant you’re looking for or you simply want to know more about who we are and what we do, we invite you to get in touch with us today. A member of The Plant Company team will get back in touch as soon as possible.
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