Product: Thryptomene, Grampians Thryptomene, Victorian lace flower

Botanical name: Thryptomene calycina THRy

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Quality specifications for Australian wildflowers

Product: Thryptomene, Gram

pians Thryptomene, Victorian lace flower

Botanical name: Thryptom

ene calycina

Thryptomene is an important filler product from the Myrtaceae family, to which waxflower belongs. It has similar postharvest handling requirements to waxflower.

Slender arching stems bear dense masses of tiny white to pink flowers at the tips. Each 5-petalled flower (3–5 mm across) develops in the leaf axils of the current season’s growth and has a nectar-filled central hypanthium (the floral structure consisting of the bases of the sepals, petals and stamens fused together). The small, dainty leaves are an attractive, fresh, mid green.

Early- and late-flowering selections have extended the production season, and several cultivars have been developed; e.g. ‘Ivory Lace’ and ‘Coral Lace’.

There are opportunities to grow other species of Thryptomene as cut flowers. Later stages of Thryptomene are also accepted in some markets – by this stage, the flower petals have been replaced by the developing deep pink to red sepals (very similar to the petals). Late in the season, grow-through becomes a problem and postharvest flower drop increases.

Flowers open first at the base of the flowering stem. As they mature, stems bear a range of flowers of different maturities, ranging from the youngest at the tip to the oldest at the base. For optimum quality, it’s important to pick stems with 50%–80% of flowers open.

Thryptomene dries out very quickly, so it’s important to keep flowers cool and well hydrated throughout the marketing chain and to quickly market the flowers.

There is considerable variation in plant form, flower size, flowering time and uniformity of flowering. The cut-flower market prefers selections with an upright habit and long arching stems densely covered with flowers. Pruning during and after flowering is important to promote flowering stems for the following year.

Plants need reasonably well drained, acidic soils. They are highly susceptible to Phytophthora root rot. They tolerate only light frosts. Plants need adequate moisture, especially during flower initiation (late November to April). Growers need to ensure that plants are well irrigated and fertilised to maximise stem length at harvest. Water stress can cause flower and leaf drop. Grow-through at the stem tips can be a problem later in the season, and is minimised by avoiding excessive irrigation and fertilising in the lead-up to flowering. Webbing caterpillars, stem borers and thrips can be important pests.

Thryptomene dries out rapidly after harvest. Two methods can be used to minimise this:

1. Some growers keep the flowering stems out of water but spray them with water, cover them with a wet cloth, and then pack and transport them wet. A retailer or florist would need to recut the stems and place them in deep postharvest solution or flower food to rehydrate them. This method may increase the risk of botrytis damage.

2. Quick postharvest handling, cooling, holding stems in deep postharvest or hydrating solution when necessary, and covering the flowers with plastic may be equally effective.

Flowering season: May–September, with peak flowering in July–August. Late-season (red) product is available in November.

Typical vase life: 7–14 days. Export can greatly reduce the vase life, especially if the transport conditions are not cold, the product dries out, or transport takes too long.

Other products to which this specification can be generally applied: Selections and cultivars of Thryptomene calycina and other Thryptomene species.

STAGES OF OPENING

COmmON dEFECTS

Stem with poor flowering and sparse branching – discard

Dried-out flowers – do not market

Stage 1Immature stage – flowers showing colour but still tightly closed: unacceptable to markets

Stage 2Slightly immature – 30-50% of flowers open: early stage, preferred by only a few markets

Stage 3Prime stage for domestic markets – 50%–80% of flowers open

Late-harvested product; missing foliage – do not

harvest

Missing flowers and foliage and bare twigs – discard

Awkwardly branched stem; bare patches due to missing

foliage – discard

Uneven flowering and missing flowers – discard

Product: Thryptomene

Common defects to be avoided at market entry:

n Overmature or dried-out product

n Poorly branched flowering stems

n Missing flowers

n Presence or signs of insects, e.g. borers and webbing caterpillars

n Tip grow-through

n Stems with sparse or uneven flowering

n Missing or damaged foliage

Stage 4Late-harvested product – flowers changing from white to pink as petals are replaced by developing sepals: accepted in only some markets

Stage 5Mature stage – most flower petals have been replaced by deep pink to red sepals, grow-through starting: accepted in only some markets

Stage 6Overmature stage – flowers are falling and grow-through is more pronounced: not accepted

Mature – white stage (stage 3) Pink–red stage (stage 5)

Tip grow-through (late-stage product) – do not market

No distinct single head or top to flowering stem – discard

Split branch – discard

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.

Typical bunches look like this (shown with and without sleeves)

‘FLOWERS’

Appearance Buds pink and flowers clear white when open.

Flowers clustered densely and evenly along and around the stem.

Not dull or dried out.

No wilting. No flower drop.

When to harvest

When 50%–80% of flowers are open, and clean white (some pink in some varieties) is clearly visible (stage 3 on chart).

Damage <5% of flowers deformed or damaged (including mechanical damage and discoloured petals).

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 Fresh, crisp appearance, uniformly mid green; no yellowing.

No leaf drop.

At harvest There is no need to remove leaves from the lower stem.

Damage <5% of leaves damaged.

Minimum evidence of pests, such as webbing or borers, and disease.

Other blemishes <5%.

Free of visible chemical residues.

STEMS

Appearance Well branched and balanced. No awkwardly branched stems.

Rigid and strong enough to support blooms, without being too woody and bulky.

Bend <30°.

No significant grow-through (in which shoots at the stem tip grow through the flowers): maximum 3–5 cm soft tip growth beyond flowers (soft tips will wilt after harvest).

Neatly cut end.

Length According to market demand – typically 50–80 cm (measure from base to the top flower).

RECOMMENDED HANDLING AT HARVEST

During harvest, minimise drying out and exposure to heat.

Transport promptly (in <1 hour) to a cool, shaded packing shed and then cool quickly to 2–4 °C.

GRADING AND BUNCHING

Grading Reject any contaminated stems.

Sort stems according to flower maturity, length and thickness.

Stem length According to market demand. Typically:

Stem length (cm)

80

60–70

50–60

Bunching Flowering stems are marketed in bunches. Bunch size depends on market demand, typically 350–450 g per bunch. The number of stems per bunch is determined by their length and by market and buyer requirements: typically 10–15. Presentation is important. Stay consistent for the grade and make all bunches the same.

Use 2 ties, 1 near base (3 cm from bottom) and another 12 cm from the base. Two ties make it easier to pack.

Especially for export, stems should be approximately the same diameter within a bunch, with the ends aligned.

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

HOLDING AND STORAGE

Cooling Effective cooling soon after harvest is important to retaining quality and maximising vase life. There are two options:

• Cool, process, cool – for example, remove field heat by cooling flowers immediately on entry into shed to 10 °C in buckets of solution, process flowers (bunch, grade), and then cool to 2–4 °C by either forced-air cooling (if boxed) or holding overnight in a cool room.

• Process within 1 hour of cutting, and then cool to 2–4 °C by either forced-air cooling for 20–30 minutes (if boxed) or holding overnight in a cool room (if in buckets). Forced-air cooling of packed flowers is ideal for large volumes.

Some growers wet the flowers before cooling or processing.

Temperature and humidity

If flowers need to be kept, hold in a high-humidity cool room (95%) at 2–4 °C.

Other ways of achieving high humidity are to cover flowers with plastic sleeves, plastic sheets or wet cloth, or to spray them with water. Sell quickly.

Product: Thryptomene

HOLDING AND STORAGE cont’d

Anti-ethylene treatment

Thryptomene calycina is sensitive to external ethylene, which causes flower drop in high humidity, e.g. in a package. If the flowers are likely to be exposed to ethylene and will be held at high humidity, or if flower drop is a problem, anti-ethylene treatment is recommended. There are two alternatives:

1. Use 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 (concentration, temperature and duration of treatment). Uptake may be less effective if flowers are poorly hydrated before pulsing. Check uptake by your flowers as described in the Postharvest Manual* and do your own trials to optimise the procedure: over-pulsing can have adverse effects (e.g. rapid closing and shrivelling of flowers).

2. Alternatively you can add EthylBloc anti-ethylene sachets to cartons when the flowers are packed (see ‘Packaging’ below).

Postharvest solutions

Postharvest solution: Transfer flowers to deep (20 cm), clean water, preferably with added reputable commercial postharvest or hydrating solution, or a registered biocide, and cool to 2–4 °C.

Holding solution: Same as postharvest solution.

Longer-term storage

For longer storage seek professional advice, and test in the market before committing product.

Trials have shown that storage for 3 weeks is possible when stems have been dipped in registered fungicide and stored in boxes lined with moist newsprint at 0–2 °C.

PACKAGING

Pack bunches of similar size (stem number, weight or thickness) together.

Put bunches of similar length together, and ensure all bunches meet this specification.

Pack boxes according to customer requirements.

Pack bunches firmly but ‘springy’ so the product will not move and be damaged. But packing too tightly can damage flowers during transit.

Pack bunches head to tail.

Some growers wet the bunches before packing them.

Use boxes with holes to allow forced-air cooling and ventilation.

Boxes are usually lined with paper.

If EthylBloc anti-ethylene treatment is required, add the sachets to the cartons according to the manufacturer’s instructions when the flowers are packed (efficacy may vary depending on packing situation).

Cool 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, preferably at 2–4 °C, but not 0 °C. Don’t transport with ripening fruit.

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

Fungal decay in storage due to botrytis (grey mould)Insects (for export)

If botrytis is likely to be present, if flowers will be held at high humidity, or if flower drop (which might be caused by botrytis) is a problem, effective preharvest management with fungicides is essential, especially within the 2 weeks before harvesting.

Effective management of insect pests before harvest is essential, especially within the 4 weeks before harvesting. Use preharvest insecticide sprays to reduce the pest population at harvest.

Dip flowers that are to be packaged and held for any significant length of time (e.g. exported) in a registered fungicide and insecticide solution with added wetting agent for not less than 1 minute, then dry naturally for 2 hours to ensure thorough disinfestation.

Alternatively, fumigate with a registered insecticide with stems in water containing a postharvest or hydrating solution or a registered biocide.

Ethylene sensitivity and anti-ethylene treatment

Thryptomene calycina is sensitive to external ethylene, which causes flower drop at high humidity. Fully mature or old flowers may be more prone to damage. Sources of external ethylene include engine exhaust fumes, ripening fruit and vegetables stored with the flowers, and the flowers themselves, especially if they are stressed or diseased (e.g. infected with botrytis).

See information under ‘Anti-ethylene treatment’ opposite.

JN: 10013 • Layout by W

ild Poppy Design • Edited by M

atthew Stevens, ScienceScape Editing, Sydney

Authors: Bettina Gollnow and Dr John Faragher. Photographs: Lowan Turton and Dr Ross Worrall. This publication is one of a series of Quality Specifications for Australian Wildflowers. ISSN 1440-6845. ISBN 978-1-74254-030-6. RIRDC Publication No. 10/057. 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.

Messages for importers and wholesalersn Recut stems and place into deep (20 cm) fresh water containing a reputable commercial

postharvest or hydrating solution, a registered biocide or flower food.n Cool product before marketing or sending on and keep it cool and dry.n Maintain good hygiene and keep containers clean.

Messages for retailersn Recut stems and place into deep (20 cm) fresh water containing cut-flower food or a

registered biocide.n Use clean buckets and containers for displays.n These flowers will benefit from misting.n Do not display flowers in areas that are exposed to full sun, draughts, high temperatures

or vehicle exhausts, and preferably 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 These flowers will benefit from misting.n Do not display in areas that are exposed to full sun, draughts or high temperatures.

Keep as cool as possible without freezing.