Product: Grevillea flowersBotanical name: Grevillea spp. and hybridsCultivar: ‘Moonlight’ GR

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Quality specifications for Australian wildflowers

Product: Grevillea flowersBotanical nam

e: Grevillea spp. and hybrids

A number of species, hybrids and cultivars of grevillea with terminal flowers have become popular cut flowers, mainly on the domestic market.

Breeding and selection are increasing the range of flower colours and forms. Tropical hybrids such as the example cultivar ‘Moonlight’, with its creamy white blooms, appear to have the greatest potential as cut flowers. ‘Moonlight’, with olive green fernlike leaves, produces flowers at the tip of both the leader and axillary branches. Other grevilleas offer yellow, greenish yellow, pink, orange and red blooms. Vase life can vary with cultivar, so those with a longer vase life should be grown.

The typical bloom is usually cylindrical or conical and consists of many individual florets, which open from the base of the bloom. Each individual floret initially splits open. The pin-like style then reflexes, first ‘looping out’ from the flower head, and later fully releasing and pointing out from the head. Flower opening and maturity are determined by the number of individual styles along the bloom that are looped. This varies between grevilleas. Harvesting at the correct stage of opening is critical for maximum vase life.

Grevillea flowers have a relatively short vase life. They not usually exported from Australia, although they could be, as other countries have a significant grevillea export industry. For example, Israel exports large volumes of ‘Spiderman’, which has a good vase life.

Grevillea foliage is another product. In addition, disbudding (removing the terminal flower bud) may force development of a multiple flowering stem, yet another product.

Attention to pruning the bushes will maximise the number of strong, marketable stems. Flowers produced during the hotter months appear to have a shorter vase life than those produced in winter.

Some people are allergic to grevillea foliage and suffer rashes and irritation.

Flowering season: All year round (‘Moonlight’), but mainly from November to May.

Typical vase life: 3–7 days

Other products to which this specification can be generally applied: Grevillea species, hybrids and varieties with terminal flowers; e.g. ‘Majestic’, ‘Honey Gem’, ‘Honey Comb’, ‘Sylvia’, ‘Bulli Beauty’.

Typical bunches look like this

STAGES OF OPENING

COmmON dEFECTS

Poor-quality bunch that is also overmature – do not market

Stage 1 Immature stage: unacceptable to

markets (<10% florets split)

Stage 2Slightly immature: early stage, preferred by only a few markets (70%–100% florets

split and 0%–10% of styles looped)

Stage 3Prime stage for domestic markets

(100% of florets split and 10%–50% of styles looped)

Stems at different stages of maturity in same bunch – do not market

(aim to have stems of similar maturity in the bunch)

Poorly tied and finished bunch – fix before marketing

Secondary flower head – remove before marketing

Product: Grevillea flowers

Common defects to be avoided at market entry:

n Overmature flower heads

n Damaged or deformed flower heads

n Dropping flower parts

n Multi-headed stems

n Uneven arrangement of flowers on head

n Stems of mixed maturity in same bunch

n Frost damage to flowers, leaves and/or stems

n Damaged or discoloured foliage

n Bent stems

STAGES OF OPENING

Multi-headed stems – due to earlier frost damage to shoot tip (this is

an atypical product and may not be accepted by all markets)

Stage 4Latest stage to market

(50%–100% of styles looped)

Stage 5Overmature stage (100% of styles looped

and <10% of styles released – sticking straight out at the base of the flower)

Overmature flowers – do not market

Deformed bloom – discard

Curved flower head – discard

Bent stem – discard

Frost-damaged leaves – discard stems with poor-

quality foliage

The stages shown apply to the product at market entry. Pay attention to the weather, time of year, and mode and duration of transport, because the flowers will continue to open during transport. You must consult with your target market to ensure that the flowers arrive at the desired stage.

Stage 6Very overmature stage: unaccepted by

many markets (>10% of styles released)

Iron-induced chlorosis or yellowing of the leaves

– discard stems with poor-quality foliage

Discoloured leaves due to nutritional problem – discard

stems with poor-quality foliage

RECOMMENDED HANDLING AT HARVEST

Grevillea flowers dry out and wilt very quickly. During harvest, minimise drying out and exposure to heat – pick when it is cool, and place straight into buckets of clean water containing a registered biocide or commercial postharvest solution. Move cut stems promptly to a cool, shaded packing area. Place in the cool room (4–8 °C) within 30 minutes of picking.Strip leaves from at least the lower half of the stem.

GRADING AND BUNCHING

Grading Reject any contaminated stems.Sort stems according to length and thickness.

Stem length According to market demand.

Bunching The number of stems per bunch varies, and is determined by bunch size, stem diameter, and market and buyer requirements. Bunches most commonly have 7–10 stems.When bunching, aim to keep flowers from interlocking, as they will be damaged later when the customer tries to separate them.Stems should be approximately the same diameter within a bunch, with the ends aligned, and tied firmly near the base.

Stems per bunch

Stem length (cm) for domestic marketLarge flowers and

thick stems60+ cm

up to 50 cm

Av. no. of stems per bunch

3

5–610 (350 g)

Sleeves Sleeves help to maintain quality by improving product appearance, limiting flower interlocking, reducing drying out and making it easier to pack. Select the sleeve size to suit the bunch size.

Product: Grevillea flowers ‘Moonlight’

FLOWERS

Appearance Colour well defined and creamy white.Flower head with densely packed florets.

When to harvest

In summer, pick flowers daily.Harvest when 10%–50% of the florets have the styles looping out from the head. In summer, no florets should be fully open (styles fully reflexed and pointing straight outwards). In winter, 2–5 of the lowest florets can be fully open.Optimise hydration by irrigating bushes the night before harvest and cutting early in the morning.Avoid harvesting when flowers are wet.

Damage No wilting.No damaged florets (e.g. styles broken).No missing florets (e.g. due to insect or bird damage).No asymmetrical, deformed or damaged blooms. Be aware that birds such as parrots are attracted to the opening flowers and can cause significant damage.

Contamination Product free of grit and soil, weeds or weed seeds, living or dead insects, and signs of insects or spiders, such as webbing.

Pests and diseases

No insects, insect damage or disease.

LEAVES

Appearance Crisp and green.Minimum foliage discolouration (<10% by area).

Damage Minimum evidence of pests, disease or other blemishes (<5%); free of visible chemical residues.

STEMS

Appearance Rigid and strong enough to support blooms.Bend <15°.Any side shoots neatly trimmed and not torn off.Neatly cut end.

Typical bunches look like this (shown with sleeve)

HOLDING AND STORAGE

Cooling Effective cooling soon after harvest is important to retaining quality and maximising vase life. The preferred option for grevilleas is:Cool, process, cool – for example, cool flowers in buckets of solution to <10 °C in the 2 hours following cutting, process, and then cool to 2–4 °C for 4 hours or preferably overnight.Forced-air cooling of packed flowers is ideal for large volumes of product.

Temperature and humidity

Hold in a high-humidity cool room (95%) at 2–4 °C until ready to process, for at least 12 hours or preferably overnight.Another way of achieving high humidity is to cover the flowers with plastic sleeves or plastic sheeting.If necessary, hold in cool room at 2–4 °C for up to 2 days.

Postharvest solutions

Use high-quality water to make up solutions. Preferably recut stems if they’ve been out of water for more than 1 hour.Anti-ethylene solution: Treat ethylene-sensitive cultivars in a commercial anti-ethylene silver solution (e.g. Chrysal AVB) prepared according to the manufacturer’s instructions (for more details, refer to the Postharvest Manual). Treat bunches according to the product label (temperature and duration of treatment).Alternatively, add anti-ethylene sachets to cartons after packaging.Hydration solution: Hold in a reputable commercial postharvest solution containing sucrose or glucose or in clean water containing a registered biocide. Solutions containing 1% glucose or 1%–3% sucrose consistently increase vase life.Postharvest solution: Same as hydration solution. No extra treatments are recommended.

Longer-term storage

Not recommended.

PACKAGING

Pack bunches of the same stem number together.Put bunches of similar length together, and ensure all bunches meet this specification.Pack bunches firmly but ‘springy’ so the product will not move and be damaged. Do not pack too tightly.Line boxes with paper and use paper between layers of bunches.Add anti-ethylene sachets to the cartons if required.Cool packaged flowers to 2–4° C before transport.

LABELLING AND DOCUMENTATION

Label boxes and buckets as recommended in Postharvest Manual* or as required by customer.Ensure box contents are exactly the same as specified in the documentation and on the end of the box.

TRANSPORT

Refrigerated vehicle at 2–4 °C for long-distance transport.

COMMON POSTHARVEST PROBLEMS Refer to Postharvest Manual* for general advice.

Fungal decay during marketing due to botrytis (grey mould)

Insects (export)

Manage botrytis before harvest to minimise risk of fungal decay, and sell cut flowers quickly to avoid the need for postharvest dips, as the styles are easily damaged.Effective management of insect pests before harvest is essential – use preharvest insecticide sprays to reduce pest population at harvest.

Ethylene sensitivity and anti-ethylene treatment

Grevillea flowers are sensitive to ethylene, which causes significant flower and bud drop. They age quickly, wilting and dropping flower parts. Sensitivity to ethylene and response to treatments varies between cultivars and may depend on how open the florets are. Commercial silver solutions, e.g. Chrysal AVB or EthylBloc, may improve vase life. However, response to such treatments has been inconsistent in trials.

Messages for importers and wholesalersn Recut stems and place into fresh water containing a reputable commercial

postharvest solution, preferably including sugar, or a registered biocide.n Cool product before marketing or sending on and keep it cool.n Maintain good hygiene and keep containers clean.Messages for retailersn Recut stems and place into fresh water containing cut-flower food or a registered

biocide.n Use clean buckets and containers for displays.n Do not display flowers in areas that are exposed to full sun, draughts, high

temperatures or vehicle exhausts, and do not display near fruit and vegetables. Use refrigerated displays if possible.

n Tell the customer how to care for the flowers and emphasise the need for cut-flower food in solutions. Give the customer a sachet of cut-flower food to take home.

Messages for consumersn Keep vase filled with the correct solution of cut-flower food. Check daily,

as flowers can use a lot of water. If cut-flower food is not used, change the water at least every second day. Always use clean vases and clean water.

n Do not display in areas that are exposed to full sun, draughts or high temperatures. Keep as cool as possible without freezing.

Authors: Dr Ross Worrall and Bettina Gollnow. Photographs by: Lowan Turton and Dr Ross Worrall. This publication is one of a series of Quality Specifications for Australian Wildflowers. ISSN 1440-6845. ISBN 978-1-74254-015-3. RIRDC Publication No. 10/042. www.rirdc.gov.au *The Postharvest Manual is the manual ‘Postharvest Handling of Australian Flowers from Australian Native Plants and Related Species’, 2nd edition, 2010. ISBN 978-1-74254-000-9. RIRDC Publication No.10/027.Both publications were developed by RIRDC Project No. PRJ-000331.

SUPPORTING INDUSTRY PARTNER: The information contained in this publication is intended for general use to assist public knowledge and discussion and to help improve the development of sustainable regions. You must not rely on any information contained in this publication without taking specialist advice relevant to your particular circumstances. The Commonwealth of Australia, the Rural Industries Research and Development Corporation (RIRDC), the authors or contributors expressly disclaim, to the maximum extent permitted by law, all responsibility and liability to any person, arising directly or indirectly from any act or omission, or for any consequences of any such act or omission, made in reliance on the contents of this publication, whether or not caused by any negligence on the part of the Commonwealth of Australia, RIRDC, the authors or contributors.© 2010 Rural Industries Research and Development Corporation. This publication is copyright. Apart from any use as permitted under the Copyright Act 1968, all other rights are reserved. Requests concerning reproduction and rights should be addressed to the RIRDC Publications Manager on phone 02 6271 4165.

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