Oioi (Apodasmia similis) – Growing New Zealand’s Coastal Wire Rush

Landscaping With OiOi

These articles give ideas for how to use OiOi in landscaping and what plants are best paired with them.

What Are Some Landscape Design Ideas For OiOi?

OiOi owe their popularity to not just their aesthetics, but also to their versatility. They are commonly mass planted on banks, used to border paths, or grown where other plants often struggle, such as wet areas. They are well suited to planting around living areas, pool, and barbecue areas where they provide interesting texture. The foliage is fantastic for providing elegance to a planting in a non-dominating manner. The Plant Company often uses them as a foundation planting at the base of short walls, or in mass plantings. They can be included in most garden styles with ease and make for a pleasant addition.

What Is An OiOi Alternative?

The most common alternatives to OiOi are Juncus, and dwarf flaxes. The leaf colouring, plant form, and growing requirements are similar with these alternatives.

What Plants Can I Grow With OiOi?

A wide range of plants can be grown with OiOi. The Plant Company often recommends using flaxes, Astelias, and Muehlenbeckia to bring in different colours, textures, and heights for mass plantings. This avoids what could otherwise become an olive-green carpet. Some popular flax options include Black Rage, Veneer, Yellow Wave, and Dark Delight.

NZ native specimen trees such as Kowhai, Titoki, and Puriri are often used with OiOi plantings. OiOi in this instance serves to accentuate the specimen tree.

The good thing about OiOi is that they are versatile and blend easily with most plant colours and textures in both a subtle and non-overpowering manner.

Oioi Care

Oioi care is about making sure the plants are thriving. Our plant care articles provide the necessary details 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 and give yourself the best chance of success with Oioi plants.

How To Care For OiOi

The most important part starts with planting, and our article, How To Plant A OiOi, 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 your plants. Organic matter such as compost or sheep pellets should be spread liberally around the plants and then overlaid with mulch. 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 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 OiOi 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.

Plants should be checked for pest or disease issues during spring, summer, and autumn. If anything is looking a little bit unusual, refer to our articles under OiOi Issues And Troubleshooting.

OiOi Fertiliser

Providing the best fertiliser for OiOi is vital for ensuring the plants thrive. 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 fertiliser articles provide the best advice about fertiliser for OiOi plants so you can achieve the amazing results you are after.

What Is The Best Fertiliser For OiOi Grown In A Pot?

OiOi grown in containers require different fertiliser to those grown outdoors in soil. In this instance the correct fertiliser to use is either 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 fertilisers 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.

What Is The Best Fertiliser For OiOi?

OiOi are vigorous plants that require feeding to keep them growing optimally. The Plant Company’s native fertiliser has been blended to give plants the boost they need and then sustained nutrition for the next 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 fertiliser 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 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.

What Is The Best Organic Fertiliser For OiOi?

OiOi are showy plants that do require feeding to keep them looking amazing. A lot of articles have all sorts of advice on this subject which often requires multiple applications so you use more of their products. The Plant Company prefers to take a simpler and more environmentally responsible approach. We believe the best organic option is The Plant Company’s organic fertiliser which is applied in spring and again in autumn and will keep them well fed. You can safely apply generous amounts of this fertiliser without risk of injuring the plants. More details about this fertiliser are provided with the product.

What Is The Optimum Soil pH For OiOi?

The soil pH refers to how acid of alkaline the soil is. OiOi prefer a soil pH within the range of 6.2 to 7.5 which means they will tolerate both acidic and semi-alkaline soils. As the pH of the soil moves away from this optimum range, the nutrients the plant is taking up (or not taking up) through the roots changes. If the shift in pH is too far, this can result in deficiencies of some nutrients and toxic levels of others. In either case this can cause the plant to become sick or even die a slow death.

The best way to know whether the pH is correct for your plant is to do a test. The Plant Company has pH test kits available that are easy to use and only take a few minutes to get a result. Preferably this test should be completed before planting so any pH issues can be corrected without risking the plant. A pH less 6.2 should have sparing amounts of dolomite lime applied along with Native Plant Fertiliser. A pH above 7.5 should have small amounts of soil acidifying fertiliser applied. In both instances the fertiliser should be thoroughly mixed into the soil before planting. A retest of the soil pH should be undertaken after four weeks, and small adjustments made again. If the pH is in the optimum range, just use Native Plant Fertiliser thereafter.

Oioi Problems

Oioi plants do have problems and disease issues from time to time. Therefore, it is important to understand the underlying issue(s) and have the remedies to fix the problem. The Plant Company have produced this series of articles to help you in the quest for answers to address common OiOi problems and disease.

Common OiOi Pests

OiOi do not suffer from pest issues as a general rule. We have seen the odd mealy bug on plants in the nursery but not at levels that would justify spraying them. That said, if pest levels are high and of concern, then a general insecticide can be used for their control. Please always read the label before using any agrichemical.

How To Control Grass Weeds In OiOi

Grass weeds can be controlled in OiOi via one of two ways. The first approach is to paint glyphosate onto leaves of the rouge grass. This requires a lot of patience but is very effective. The second method is to dig out the OiOi, remove the weed inclusions, and then put the plant back. The Plant Company recommends using mulch to reduce the chances of weeds returning.

What Is Causing The OiOi Leaves To Yellow?

Leaf yellowing can result from OiOi being grown in stagnant soil conditions, too much shade, or where the plants have not been fed for a number of years. A liquid fertiliser can be used to correct issues quickly and should be supported with Native Plant Fertiliser during spring.

What To Do About OiOi Frost Damage

If the new growth on your OiOi has been killed or damaged by frost, trim off the damaged leaves after the risk of frost has passed. Frost cloth or a blanket may be used to afford protection from further frosts. It is important not to cut off the frosted growth until the risk has passed as this growth, albeit ugly, is helping to shield the plant from further damage.

New shoots tend to be more prone to frost damage than older ones. For this reason, The Plant Company does not recommend applying fertiliser of any kind to plants between mid-autumn and late-winter as this can create softer shoots that are more susceptible to frost.

Why Are There Dead Tips On The Leaves Of My OiOi?

Small amounts of dead tissue at the ends of older leaves on OiOi is common. It is generally the result of ageing, or the plants having endured a stress such as from drying out for a period. The leaf tips can be trimmed using scissors and this won’t affect the plant.

OiOi Propagation

OiOi propagation is a relatively straightforward process when you have the right advice. OiOi are easily reproduced and our articles give you the best chance of doing this successfully and efficiently.

How To Propagate OiOi

OiOi are easily propagated by division. Established plants are simply broken apart with roots still attached. This task is usually undertaken any time between late autumn and early spring with plants potted up using growing media for several weeks before planting out again. Take care not to make plants too small as they must have plenty of roots to successfully re-establish.

OiOi can also be easily grown from seed. Fresh seed is scattered onto growing media and vermiculite used to cover the seed in a thin layer. The trays are kept warm and moist, with seeds germinating inside of two weeks.

OiOio Information

There is a wealth of information about OiOi plants and often The Plant Company is asked specific questions about them. Hopefully you’ll find answers to general questions in this series of articles.

Are OiOi Good For Controlling Erosion?

The short answer is yes. OiOi have a fibrous and spreading root system, which are perfect characteristics of plants for erosion control. They can be planted across a wide range of soil types from clay through to near sand. Such root properties also make them well suited for public spaces that are be poorly drained. On such sites will spread to colonise larger areas with time, which again, will help control erosion.

Are OiOi Good For Riparian Planting?

The short answer is yes. OiOi are generally regarded as being tolerant of wet conditions due to their fibrous and spreading root system. These are the perfect characteristics of plants for riparian margins. They will also spread to colonise larger areas with time.

Are OiOi Hardy To Frost?

OiOi can take a heavy frost once established, though very young plants should be protected until they are at least 10 cm tall. Frost Cloth is a good option for protecting vulnerable plants if you are worried. Be careful to harden off recently purchased plants if you intend to plant these during winter and frosts are likely. Do this by gradually exposing them to the cooler conditions over a 2-3 week period or until such time as you think that a frost won’t damage them. The Plant Company recommends holding off planting until spring if you are at all worried that new plants might get frosted. Generally speaking, a good sized OiOi planted in spring will cope with frosts the following winter.

Are Rushes Native To NZ?

There are over 50 species of rushes native to New Zealand, and they are found in a variety of habitats, including wetlands, forests, and alpine environments.

Some of the most common native rushes in New Zealand include:

• Apodasmia similis (oioi)
• Juncus australis (sea rush)
• Juncus effusus (soft rush)
• Juncus holoschoenus (wire rush)
• Juncus pallidus (pale rush)

How Does OiOi Spread?

OiOi is a native New Zealand plant that spreads by creeping rhizomes and stolons. Rhizomes are underground stems that grow horizontally and send out roots and shoots. Stolons are above-ground stems that grow along the ground and send out roots and shoots at their nodes. OiOi can also spread by seed, but this is less common. The seeds are dispersed by wind and water. Once the seeds germinate, the seedlings will develop rhizomes and stolons, which will allow the plant to spread further.

How Fast Do OiOi Grow?

OiOi are generally vigorous, establish quickly, and will double in size each year. Be sure to start with strong and healthy plants at the outset.

How Tall Will My OiOi Grow?

OiOi typically reach 60 cm tall and about 50 cm wide, but this obviously depends on the growing conditions. The Plant Company has put a lot of effort into determining how big each plant will grow in an unrestricted growing environment. Far too often we see people planting a garden too densely and then having to spend a lot of time trimming or removing plants later. This is something we want our customers to avoid, and we therefore provide size information so the planning can be right from the start. Be sure to check out our OiOi and the detailed information that accompanies both this and our other plants.

Is OiOi Invasive?

The short answer is no. It grows as a spreading clump and rate of relatively slow rate of spread does equate to it being invasive. Plants can spread through seed dispersal, but in this instance, they tend not to establish in an invasive manner.

What Is The Common Name For Apodasmia Similis?

Apodasmia similis has several common names:

• Oioi: This is the most widely used common name for the plant, especially in New Zealand.
• Jointed wire rush: This name describes the plant's jointed stems and wire-like appearance.
• Segmented rush: Similar to "jointed wire rush", this name also refers to the plant's segmented stems.
• Thatching rush: This name references the traditional use of oioi for thatching roofs in Māori culture.

Less common names include:

• Sand dune rush
• Coastal rush
• Wire rush
• In some regions, Apodasmia similis may also be known by specific Māori names, such as:
• Makīrewarewa
• Kiokio
• Popokotea

Planting And Growing Oioi

Establishing OiOi plants 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 Apodasmia similis.

Are OiOi Easy To Grow?

OiOi are very easy to grow, but you need to have the basics right. Choose a sunny spot and prepare the soil by adding compost or sheep pellets. Feeding your plants in spring with Native Plant Fertiliser will replenish nutrients and keep them fed for 12 months. They should also be watered regularly during dry periods to keep them flourishing.

Can OiOi Be Grown In A Pond?

Yes, OiOi can be grown in ponds and other non-saline water areas. The depth of water they are grown in should not exceed 10 cm and the water should be near still. OiOi do not do well in flowing or stagnant water.

Can OiOi Be Grown In Coastal Environments?

OiOi can cope with coastal areas provided they are not routinely covered in salt spray. Being constantly coated with sea spray can result in leaf burning. If the soil is too saline, this can also prove detrimental to the plants and result in them becoming stunted. If you elect to plant in this environment, The Plant Company recommends ensuring the soil is well prepared with organic matter such as compost and provide some shelter with regular watering, particularly during dry periods.

Can OiOi Grow In Pots?

OiOi can absolutely grow in pots and they look amazing when managed appropriately. Choose a pot that is no more than twice the size of what the OiOi is currently growing in and that has plenty of drainage holes in the bottom. Fill the bottom of the pot to about 1/3 of the way up with potting mix. Do not use soil or compost when growing plants in a container and do not add fertiliser. The Plant Company potting mix has all the nutrients required to sustain the plant for the next 12 months.

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, especially for larger grade plants, to minimise any chance of damaging the roots. Place the plant in the hole without removing any of the growing media or cutting the roots. You can tease them apart if you want but this is not essential. If the roots have been circling the inside of the pot or they look totally root bound, you don’t need to cut them. Add more potting mix and firm this around the plant using gentle pressure, then water well. They should be watered twice a week during hot weather and weekly or fortnightly during cooler periods.

The key to having an amazing OiOi in a pot is to both keep it fed correctly (see article Best Fertiliser For OiOi Grown In A Container) and keep it well watered. This is one plant that is generally not killed by over-watering.

Can OiOi Grow In Shade?

The answer to this question depends on how much shade. In shaded conditions OiOi tend to become “leggy” or “floppy” as the leaves extend to find light. In full sun they tend to be more compact and denser, with better colouring. 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 overall aesthetics are likely to be less than if they were growing in better light.

Can OiOi Grow In Wet Areas?

The short answer to this question is yes. OiOi grow naturally in lowland and on the margins of swamps. Therefore, they tend to thrive where other plants do not.

How Far Apart Should OiOi Be Planted?

OiOi look amazing when mass planted and are perfect for both banks and borders. The question about how far apart depends on how quickly you want them to fill an area as the spreading roots will enable it to colonise areas with time. As a general rule, 2.5 plants per square metre is recommended by The Plant Company, which equates to 40-50 cm apart.

How To Plant OiOi

Choose a full sun or partial shade position for your OiOi plant. The hole should be dug to 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, especially for larger grade plants, to minimise any chance of damaging the roots. Place the plant in the hole without removing any of the growing media or cutting the roots. You can tease them apart if you want but this is not essential. If the roots have been circling the inside of the pot or they look totally root bound, you don’t need to cut them as this will set this plant back.

Now the plant in the hole, 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.

What Is The Best Soil For OiOi Growing In A Pot?

Only potting mix should be used when plants are grown in a container. Often people will try and cut corners and use soil or mixes that contain both soil and potting mix with poor results. The same applies to when plants are potted up with compost as it holds too much moisture. Soil also contains weeds and tends to become compacted in a container, hence why it is not used in this manner. The Plant Company has nursery grade potting media which is pre-loaded with the correct amounts of fertiliser and micro-nutrients to keep the plant sustained with nutrition and actively growing for the next 12-months. After 12-months, simply add a couple fertiliser tablets to keep the plant fed for the next 12-months.

What Is The Best Soil For OiOi?

Soils rich in fertility and organic matter that are well-drained will produce amazing plants. The soil should be well prepared with either compost or sheep pellets mixed in at planting or spread on the soil surface after planting. It is important that the soil being planted into won’t restrict root growth and for this reason, clay soils are generally not well suited to OiOi. Clay soils also tend to be very wet which will negatively impact the performance of the plant. That said, OiOi are a good selection for such soils as the options are limited.

Feeding your OiOi plants in spring with Native Plant Fertiliser will replenish nutrients and keep them fed for 12 months. Liberal amounts of organic fertiliser can also be used. Do ensure that plants are watered regularly during dry periods to keep them flourishing.

What Mulch Should I Use Around OiOi?

Placing mulch around OiOi helps keep the soil moist and significantly reduces weeds. The Plant Company recommends an organic mulch is used as this breaks down over time to provide nutrients and improves the soil. It is also better for the environment than the plastic-based alternatives. Whatever type of mulch is used, it needs to be free draining so the soil can “breathe” and allow water to penetrate quickly and easily. Heavy rates of lawn clippings are therefore not a good option as they hold too much moisture. 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 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 recommends stones, bark chip, or other similar products be spread over top for aesthetic purposes.

Compost is not considered an effective mulch as weeds germinate easily and it is only short lasting. It is, however, a very good method of adding organic matter to the soil and should be applied before the mulch is put down.

When Is The Best Time To Plant OiOi?

OiOi 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 any time from late-autumn through until early-spring. Make sure you have a good planting spade to make this job a lot easier.

Where Do OiOi Grow Best?

A full sun or partial shade position is essential for getting the best results with OiOi. They can grow on poorly drained sites but will always do better on soils that have good drainage.

In shaded conditions OiOi tend to become “leggy” and somewhat “floppy” as the leaves extend to reach light. In full sun they tend to be more compact and denser, with better colouring. The planting position should also be moderately sheltered which will help both with establishment and to produce a better shaped plant overall. This latter part is not essential as they can cope well with wind.

Trimming OiOi

Decisions about when to trim an OiOi plant, how to cut them back, and how hard, and even how to do this task can be daunting for the novice gardener. The Plant Company have produced this series of articles to provide advice for how to trim OiOi so you can manicure your plants with confidence and success.

How Hard Can I Prune My OiOi?

OiOi will sprout when cut right back, even close to ground level. However, this relies on the plant having heathy shoots at the outset. This activity is best undertaken during spring or summer using secateurs. Please note: OiOi grown in shade environments may struggle to re-establish when cut back severely. The Plant Company does not recommend cutting plants any lower than 10 cm above ground level to ensure a better chance of success with this procedure.

How To Trim An OiOi

OiOi are generally only trimmed to remove unsightly leaves or cut back more aggressively to rejuvenate or control a plant. This is best done during spring or summer when plants are moving to active growth. Aggressive trimming usually involves cutting plants back to 5-10 cm above the soil level. OiOi are very forgiving plants and even if you get the trimming wrong, they will generally recover! Unfortunately, there is a risk of plants dying after such aggressive trimming. This will sometimes occur if the plants were diseased or suffering nutritional deficiencies ahead of trimming. In these cases, the plant wouldn’t have had the reserves to resume active growth.

Light trimming can involve cutting the brown tips off plants, cutting out yellow or sickly-looking leaves, or even thinning out the foliage. This can be done at any time.

When Is The Best Time To Trim OiOi?

OiOi can be trimmed at any time of the year, though spring is the time recommended by The Plant Company for any aggressive cutting back. The plants sprout from the base and at this time of year they are ready to bounce into active growth with the warming weather. Light trimming to remove unsightly foliage can occur at any time of year.

Watering OiOi

Watering OiOi correctly is an important part of growing amazing plants. Importantly, making sure your Apodasmia gets enough water is paramount. Our articles provide advice and guidance on this subject.

When To Water OiOi?

OiOi require good levels of soil moisture to stay fresh and keep growing actively. They require watering both during establishment and during dry periods. The Plant Company recommends a generous watering every second day during summer, or every third day if the soil is a bit heavier. If plants start to droop, you need to water immediately. The Plant Company advises watering in the morning or in the evening for water conservation purposes.

During dry periods OiOi may stop growing to preserve themselves. This is clearly not desirable if you are still wanting them to grow. They will start growing again once rain or water is provided and as long as they have not been allowed to desiccate.

If OiOi is being grown in a pot, watering 2-3 times a week during summer and once every 10 days during winter is the general rule. This will depend on how hot the growing environment is and the size of the plant. The good thing about OiOi is that you won’t kill them with over-watering.