Seedlings grown in Ngaruawahia

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Dianne Patterson writes of her visit to the Forest Flora Nursery which provides seedlings for the Trees for Survival programme in the Waikato Region:

Waikato River and Hakarimata Range

Travelling south following the Waikato River, the Hakarimata Range was on my right and entering the township of Ngaruawahia I spotted my destination, the Bennett’s. After a warm welcome by manager Julia Grimm and owner Wayne Bennett we set out to tour their vast establishment.

Julia Grimm and Wayne Bennett

For the fourth year, this native plant nursery will provide approximately 1,000 native plants per 6m plant growing unit, to be distributed to 22 Trees for Survival schools in the Waikato region. In May the first of three lots will go out with each punnet providing about 100 seedlings for children to prick out into root trainers and later pot on into PB3/4s.The final set of punnets will go out in September.

Punnets germinating Trees for Survival seed

Ribbonwood seedlings pricked out – see footnote 1

Species provided for the Trees for Survival programme are mainly revegetative species such as Plagianthus regius (ribbonwood or mānatu) Leptospermum scoparium (manuka or tea tree), Kunzi ericoides (kanuka, also known as tea tree) Phormium tenax (flax or harakeke), Carex germinate (sedge), Cordyline australis (te kouka or cabbage tree) and Coprosma robusta (karamu).  Accurate information is provided about all the plants supplied at the nursery in an attractive format on the Forest Flora website. For example see pictures and notes on karamu at

About Forest Flora Nursery

The philosophy underlying actions at the nursery is that “Forest Flora is committed to sharing the knowledge and understanding required to restore ecological processes and make revegetation effective, affordable and attractive … all their business activities … are expected to be environmentally sound, socially constructive and financially sustainable”.

Their core business is ecological restoration or reconstruction. Julia aims to supply the community with 100,000 native trees and plants each year.

There are about 100 different species in the nursery, many relatively rare, and there may only be five plants of one kind. Julia commented that there are never enough trees, and ideally customers  should be ordering a year or two in advance of a planned planting, since some species require as long as a year just to germinate.

Over the past 30 years, Wayne has established a diverse range of native NZ trees amongst mature stands of kanuka bordering older bush, including a gateway of elegant towering rimu. Wayne is currently the coordinator for Ecosourced Waikato, a project manager for Waikato Rivercare and is on the committee of Ngaruawahia Action Group. He has a fascination for wild places, natural systems, and native plants and animals.

Julia has a background in Environmental Planning and her involvement with Trees for Survival comes from a belief in “teaching the next generation to learn the importance of native planting”.  She loves the fact that she has an outdoor office and lifestyle.

Clients of the nursery include DOC, Waikato Regional Council, NIWA, Waikato District Council, Waipa District Council, private landowners (farms, lifestyle blocks and town properties) and Trees for Survival Charitable Trust.

Waikato Rivercare Restoration project

Forest Flora was contracted to the Waikato Rivercare Restoration project and supplied plants for a 2km stretch of the river which they continue to monitor. Species not commonly planted are doing well, following their intent to echo the natural mix of native species in the region and so to contribute to biodiversity. Referring to their website; “We focus on the native plants which would naturally occur in an area, as these form the structure of an ecosystem and are an essential step in its reconstruction”.

Waikato Rivercare Restoration Project Hakarimata Road, Ngaruawahia

Collection, Stratification and Germination of Seeds

Seeds are eco-sourced and mostly collected between January and April. Forest Flora sits on the boundary of three ecological districts: Raglan, Waikato and Meremere. Wayne has built up an excellent knowledge of “all the old trees on the river”. Seed collection is dependent on nature, so they watch for the good year’s master crops, and will then drag a ladder for kilometres into bush to be able to collect, for example, seeds from a good year’s crop of kahikatea – see footnote 2.

Collected seed is carefully labelled according to botanical name and the source location. They are then refrigerated and stored until needed. Sometimes this depends on demand for certain species and it is simply a matter of the nursery having space to propagate them – see footnote 3.

Later, usually in Spring, the seeds are sown into trays of pure vermiculite, or a seed raising mix with a covering layer of vermiculite, under covers of black plastic cloth; again carefully labelled as to their species name and eco source – see footnote 4.

In the greenhouse Wayne showed me a tray of kauri seedlings emerging from the silvery flakes of vermiculite. Just a couple of weeks earlier he had found a ripened cone from which the seeds fell easily, and he’d had a good rate of success.

Julia prefers to hand water the emerging seedlings as needed, so as to keep a close eye on the process whereas an automatic sprinkling system might invite neglect. It is also necessary to have rodent control and sometimes insect control. A tray may hold as many as 2,000 seedlings which then need pricking out. Julia prefers to use trays that house about 100 seedlings in individual tapered, square and flat propagation pots. She finds her system is space efficient and recognises the ease of potting them on into 1.3 litre pots, compared to using root trainer systems. Usually clients return the plastic pots for reuse.

Kauri seedlings emerging in vermiculite

Julia in potting shed

Kahikatea seedlings pricked out in small plugs

Titoki seedlings in 1.3 litre pots

Kakakawa seedlings standing in a naturally shaded area are testimony to the vibrancy and good health of the nursery plants.

There are vast areas of benches under shade cloth housing trays of seedlings in plugs. One area of levelled paddock is nestled amidst native bush which provides shady areas for species like kawakawa, and protection from strong wind and heavy frost. Grouped by species, the pots stand on weed mat.

Further south on the Waignaro Road, the Bennetts have leased an old quarry site where thousands of trees in PB8s weather the full sun and frosts, hardening up before they are planted out. Some, like totara, kanuka and kahikatea are over a metre tall, ready to plant out and stand tall above summer growth of grasses and weeds.  Here also Wayne has been planting alongside a stream, learning first hand which species thrive and which suit the various microclimates provided along its length.

Waignaro Road site, Hakarimata Scenic reserve behind

Julia shows Kanuka sapling & mature kanuka

In the process of re-establishing native flora it’s worth considering, Wayne says, “What are the risks of short term erosion in the removal of certain weeds, before new plants become established?” In advising land owners about weed removal, including willows, Wayne offers advice based on his years of observing which native species thrive in the shade and amongst roots of willows, which weeds are invasive once the willows are removed, and the threat they then impose to successfully establishing re-vegetation. Factors include whether or not there are nearby populations of willow which will easily reseed the cleaned area.

Wayne in nursery with an area of bush he established

In conclusion, Wayne says, “I’d like to see more small nurseries established to meet the increasing demand for native plants, and to support educational programmes such as Trees for Survival where people are planting and children are growing our future”.


1. Ribbonwood

Ribbonwood (Plagianthus regius), or mānatu, grows on fertile soils in lowland forest, along river terraces and at the margins of forest. It can grow to a height of 17 metres, making it New Zealand’s tallest deciduous tree. As an adult it develops a tall trunk with wide spreading limbs, but in its juvenile form it is a small-leaved, highly-branched, slender bush. Like the lacebarks, ribbonwood has an inner layer of bark made up of net-like layers.

Source: Joanna Orwin. Shrubs and small trees of the forest – Lacebarks and ribbonwoods, Te Ara – the Encyclopedia of New Zealand, updated 8-Jul-13

2. Ecosourcing

Eco sourcing restores natural populations and avoids introducing plants from other areas. This helps to maintain the distinctive local character of an area. Eco sourcing also aims to propagate from enough individuals to ensure the new planted population truly represents the range of characteristics found in the original population. This is important to avoid inbreeding, help the species cope with change and survive in a range of environments.

3. Stratification

In horticulture, stratification is the process of treating stored or collected seed prior to sowing to simulate natural winter conditions that a seed must endure before germination. Some seed species undergo an embryonic dormancy phase, and generally will not sprout until this dormancy is broken. The time taken to stratify seeds depends on species and conditions; in many cases two months is sufficient.

4. Vermiculite

Vermiculite is used as a soilless growing media. Exfoliated vermiculite is combined with other materials such as peat or composted pine bark compost to produce soilless growing media …These mixes promote faster root growth and give quick anchorage to young roots. The mixture helps retain air, plant food and moisture, releasing them as the plant requires. Either used alone or mixed with soil or peat, vermiculite is used to germinate seeds. Very little watering is required. Source

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