Rainfall varies around 1000 mm/year, is mainly in winter from frontal NW rain, the summer prevailing winds are from the SE, temperatures seldom rise over 32 degC, winter is usually above 8 degC. Proximity to the south Indian Ocean ensures moist air, the soil is well-drained with a pH of around 5.5. The property borders on the Kogelberg Biosphere Reserve where the higher areas can receive 2000 mm pa in rain and cloud condensation, in certain areas the soils are almost peaty in makeup.

Inland it gets progressively drier, and the higher parts have occasional snow, though never for long. The soil varies, is mostly acidic, and is characterized by low nutrients and an almost complete absence of phosphate.

The post The natural environment of Betty’s Bay appeared first on How to grow Proteas.

There are pathogens prevalent in the environment that play a limiting role to the regeneration and growth of species. While some long-associated pathogens are more-or-less in balance, others have arrived relatively recently and can be a big problem.

Naturally, for experimentation purposes, the availability of seed or clonal material of critically endangered Proteaceae is limited and germination or rooting is often of a “one chance” event. Legal procedures and permissions to collect material in the wild can be laborious.

The maintenance of ex situ mother plants is a key aspect for experimentation and further growth of a collection. My aim has been to develop a few viable, healthy mother plants (grafted or on their own roots) ex situ, propagate from these and record observations and trials to establish protocols for multiplication that can be used in the future to mitigate against approaching climate changes, population growth and the possible loss of knowledge and skills due to natural staff turnover in botanical gardens.

The post Assembling a collection of plants for propagation appeared first on How to grow Proteas.

A simple bare bones instruction on how to germinate these seeds does not give one a deeper appreciation of the ecological workings of the Fynbos Biome of which these plants form an integral part.

The hard, nutlike seeds (more scientifically named achene) of Leucospermums and Mimeteses are collected by ants after they have dropped from the flowers and stored underground in their nest where they are relatively safe from mice and rats. These seeds have a soft outer coat (elaiosome see fig 1) that has a pheromone that attracts both the ants and mice. This coat is utilised by the ants, and they store the seeds underground before the mice can get to them.

The seeds of the Protea are not stored underground, instead they are dispersed by wind after the plant has been killed by periodic fires and the seed heads have opened, releasing the seeds. As each seed head may produce five to ten viable seeds amongst hundreds of other non-viable seeds this may confuse the mice predators. These seeds have no ant attractor.

The post Seeds in the natural environment appeared first on How to grow Proteas.

As more frequent human induced fires have been occurring for a very short time, the natural evolution of seed storage and germination strategies lie in the deep past and one must assume that the majority of fires that started over previous millions of years were caused by lightning or earthquakes (leading to falling rocks). In the mountainous fynbos region of the Cape, the lightning season is around the equinoxes, just prior to the onset of the winter rains when the fynbos is summer dried. The lightning is more often “sheet” as opposed to ground strikes that actually start the fires. Stronger earthquakes also start fires but they are not seasonal nor in any way frequent.

The intensity of the flames during a veld fire plays a part in germination. The deeper the ants bury the seeds, the less a cooler fire can penetrate and there is no effective heat pulse except to the shallowest buried seeds which may or may not help break dormancy (more about this later). In fact cooler fires allow the deeper seeds to maintain their dormancy and are preserved for the next hotter fire. A neat way of not putting all the eggs into one basket as there may be a poor survival rate of the shallow seeds due to other conditions.

Another way that the risk is spread lies within the seed itself as the freshest seeds need a few years of maturing before they germinate. Leucospermum conocarpodendron seeds have a lower percentage germination rate in their first year from seed drop while 1-year-old seeds are better, both under laboratory-type conditions. This allows some of the most recent seed to be carried over to the next fire, thereby ensuring that there is a lessened chance of local extinction.

Mimetes stokoei was considered extinct as there had been no new plants seen for 50 years and after three cool fires had passed over the seeds in the ground, it is believed a hot enough fire contributed to their subsequent germinating.

The post The role of fire appeared first on How to grow Proteas.

Or it could be that over thousands of germination cycles the normal (and maybe colder) cold fronts of the past are now unusual, occurring at greater intervals, leading to reluctant or delayed germination. This could have implications of global warming affecting germination cycles.

To germinate, seeds need water, warmth, cold and oxygen yet these factors are lessened underground in the ant’s nest where the temperature is more stable. If by chance they do germinate, they would be in deep shade at ground level provided by a living canopy while underground the new roots would have to compete with other mature roots. Evolution has worked to prevent the seeds germinating at the wrong time. The seeds need the sun’s warmth to penetrate though the soil above them and this will only happen after a fire when competition for scarce nutrients and root space is much less.

There is another unanswered question for me – is oxygen availability lessened underground in the ants’ nest and are the ants driven deeper underground by the fire for a time, allowing oxygen to penetrate to the higher stored seeds, thus triggering germination?

A fire heats the surface soil to an extent that pathogens and rodents are suppressed for a time and the fire ash nutrients have been watered into the soil by the first rains The prevailing conditions after a fire in the autumn is a sun-warmed soil and cooler and longer nights of the approaching winter with its promise of rain. There is a day to night fluctuation of temperatures that the seeds need to switch on as part of the dormancy break. If the seed germinates during this late autumn/early winter when the summer drought has broken it is assured of a lengthy period of regular rain, whereas an abnormally wet summer (fynbos gets most of its rain in winter) does not switch them on as the needed temperature fluctuations are not there yet. Germination in summer will only assure the seeds of heat and drought so the plants have evolved a mechanism that responds to the day/night temperature fluctuation of 10 deg C or more, and longer cool (autumn) nights.

I once tried to germinate some Leucospermum seeds at the correct time, but as they were less than a year old the germination rate was low, so I picked out the few seedlings that had germinated and forgot about the rest for a year, leaving them in the pot in full sun with no water except a little summer rain. When the temperature fluctuations started, and with no prompting from me, they started to germinate in the dry pot.

There are three protective coats surrounding the Leucospermum and Mimetes seeds, the outer, fleshy coat the ants use and the reason they take them underground safe from mice, then there is a much thinner coat that is not permeable to oxygen. This very thin inner coat when subjected to the heat of a fire flakes off in patches, allowing entry of oxygenated and smoke/ash saturated rainwater. This thin coat is difficult to mechanically abrade off and needs special attention. The last coat of the three is the strong nutlike coat that provides mechanical protection. It cannot be broken by squeezing it between thumb and forefinger, yet when exposed to a dry heat becomes brittle and crushable. Some of the stronger will germinate with simple prompting but with rare seeds, the weaker are as precious as the stronger.

The post Temperature and germination appeared first on How to grow Proteas.

Removing seed heads from a plant should be done with secateurs as snapping them off allows a greater opportunity for pathogen entry into the plant. No more than 10% should be taken from a plant and not more than 10% from a population to allow for sustainability.

The majority of Protea species retain their seeds for a few years on the plant and are mature nine months after flowering has ended. After a few years on the plant the seed viability starts to deteriorate due to water penetration and insect predation (Fig. 1). Collected seed heads should be allowed to spontaneously open and release the seeds which takes a few days. Some proteas open very slowly so with secateurs, nibble away the bracts to the edge of the seed receptacle (Protea repens, P. scolymocephala).

Viable protea seeds are generally fatter with a slightly different shape (Fig. 2). The best way to test viability is to cut the seed in half, learning as you go. Trying to sort viable/non-viable seeds is often a waste of time as the visual and/or “feel” difference is negligible or the seeds are very small (P. nana). The seeds of P. mundi, P. compacta, P. coronata, and P. magnifica, are among the easiest to sort. It should be noted that commercially available hybrids produce few if any, viable seeds.

The post Protea seeds appeared first on How to grow Proteas.

Some Fynbos seeds require a maturation period before they can germinate so they do need to be stored, sometimes for a number of years. A few months before attempting germination certain seeds benefit from a striation period of one to three months in a domestic fridge which is normally at 5 deg C., however I do not usually use this option as it is not a decisive aid for Proteaceae.

The post Storage appeared first on How to grow Proteas.

With difficult-to-sort seeds it would be easiest to try germinate the entire batch and use a larger seed tray, however the seeds will then be mixed with bracts and other chaff, the worst of which should be sorted out as fungus growth can start as the chaff begins to compost which also then attracts insects etc. A vigorous rub between the hands will separate the seeds from the styles, a sieve may be useful to separate the fine matter. A word of caution: if too much chaff and seed are sown together there is a danger of setting the seed deeper than the ideal of one centimetre or less. For this mass procedure I have sown the seeds in their tray and then soaked that tray for 24 hours in a larger tray with or without the primers. It is not necessary to position the seeds up or down as the emerging radical always orientates itself downwards.

Simply sowing unsorted seeds without any primers or smoke water has worked well for me and I do not use primers for the hairy Protea seeds. However the air temperatures should then be optimal and the medium should never dry out.

The germination of Proteaceae is reliant on the day/night air temperature varying by around 10 deg C (see Leucospermum germination), so the best time is late autumn/early winter when the days are shortening. Inevitably there are cloudier or hotter days, but this seems to matter little when the average fluctuation is 10 deg C and is cooler for a longer autumn night. I use a shallow seed tray (6cm deep x 17cm x 24cm) which allows a quicker natural warming and cooling of the medium that is required for germination to start. Watering should be done in the late afternoon after the sun is off them to aid in the drop of the evening temperatures.

The time it takes seed to germinate (till radicle emergence) varies, but the quickest is around 19 days (Protea mundi), others take 30 days (P nana, P. pityphilla, P. scolymacephela) while others can take longer (P. scabra, P. acaulos, and P. restionifolia). Once germination has begun, I sort through the seed trays every five days as often there is an initial germination, then a staggered germination after that. When working with rare seeds I allow for this and keep the seed trays damp with the same temperature variations for at least a month after the first germinations. This staggered germination may be due to the differing maturity of the plants from which seed heads have been taken, or some other factor like weaker seeds, weaker plants, slower rate of water imbibition by some seeds, position of seed trays relative to the sun angle, depth of sowing etc.

As seed sorting is often inaccurate, I feel that germination numbers per mature seed head is a better measure of viability for unsortable proteas.

Note in the following table that the grafted Protea nana seeds germinated at a very much lower rate than the ungrafted ones that were collected from a natural in situ colony, perhaps indicating some sort of incompatibility of grafting and seed viability. This is forming a long-term enquiry that may indicate a lack of the correct pollinator or some sort of graft disunity. It raised the possibility that endangered ex situ plants need hand pollinating. I hand pollinated half the flowers on a grafted Protea nana and the germination rate for the hand pollinated versus the open pollination was equally poor. I shall be using different rootstock species as well as a variety of scion species. A spray of Boron well before bud opening will be tested as this is reputed to help develop the style down which the pollen germinates.

None of these seeds had a stratification period, instead germination was initiated from room temperature storage. No smoke water, H202 or gibberellin was applied. Germination resulted entirely from open autumn temperature fluctuations and keeping the seeds damp in peat moss. As some had a better germination percentage it might be indicating that additives could have been an advantage for some species.

The post Pre-germination treatment of Protea seeds appeared first on How to grow Proteas.

At cotyledon emergence the cotyledons have control and afford protection – I prefer to think of the cotyledons as providing “mothers milk” – the perfect nutrients for the young plant. As for planting out the seed at radical emergence, my feeling is that the emerging seedling will naturally develop to the best surface level between the stem and the roots. If the seedling is potted-up too deep, this level can be below the surface and if kept too wet can afford an entry point for damping off and other problems.

Planting out from seedling trays into pots runs the risk of planting too deep, planting with a bent root or disturbing hair-like rootlets just starting to form. I find that planting the emerging seedling into a small cell at the radical emerging stage and allowing it to grow to just after cotyledon exhaustion stage is a better option as it is easier to pot up then. (Figure 2) Proteas hate their roots being disturbed so great care is needed here, especially after the cotyledon begins to exhaust itself. A drench of 5 parts seaweed extract (10ml per litre) plus fulvic acid (14 ml per litre) and salycilic acid (200 mg per litre) and sugar (2%) a few days before potting-up will be beneficial.

The post Post germination treatment appeared first on How to grow Proteas.

The hard, nut-like seeds of leucospermums and mimeteses are not stored in the canopy of the plant, instead, they drop out of the flower when mature. The seeds are collected by the ants common to the fynbos and store them underground where they eat off the surrounding elaiosome – a soft fleshy skin rich in nutrients, notably lipids and proteins. It is the reward to the ants for all the hard work of dragging them underground to their nests. These nests are usually a short distance from the plant, so seed dispersion is not as wide as hairy Protea seeds that are dispersed by wind. Once underground they are reasonably safe from mice and rats. As the soft skin surrounding the inner nut has a distinctive smell recognized by the ants and mice, there is a competition as to who gets there first. The ants preserve them, the mice eat them. The conditions inside the ants’ nest provide a steady, non-fluctuating soil temperature as an intact plant canopy keeps the sun from penetrating and warming the soil so the seeds enter a state of dormancy. The depth of the stored seed in the ant’s nest varies, but I have buried germinating seeds (at radical emergence) at various depths and at 8 cm the seeds can grow the cotyledons to the surface with a tube type of stem which transforms into a thinner root when the cotyledons emerge above ground.

Leucospermum seeds (technically a fruit classified as an achene) are released a few months after flowering and this presents a few problems in collecting them. The yield can vary greatly, anything between 0 and 18 (Leucospermum conocarpodendron) per flowerhead with the higher number being unusual. If the heads are snapped off well before seed drop, the likelihood is that the seeds will still be immature as they need a week or two between being immature and reaching maturity. Immature seeds are milky white, easily crushed while a week or so later they are turning black under the elaiosome. I have developed a “feel” when to snap off the seed head. A sideways snap and it will come off quite easily while a head with immature seeds will be more resistant. Dissecting with secateurs of the first seed heads on a plant should be done.

The collected heads can then be air-dried in shade for a few days and the seeds pried out with a spike (sharpened nail) or after a longer wait most, but not all will fall out. The viability can be around 50%. To test for viability, I strip off the elaiosomes and drop the seed into water and the floaters can be discarded. Sometimes an entire plant may yield no seeds – this is more likely with an old plant, so I assess the plant and dissect a few seed heads to check this.

Some leucospermums start ejecting their seeds on the sunward side of the flower first while the lee side may be a week or so from maturity and seed drop (e.g. Lsp. Catherinae). Others produce one, maximum two seeds (Lsp. oleifolium) per flowerhead, or none and this can be seen easily if the stamens are gently parted after the flowers have turned brown. The seed matures and darkens in the last few days before it drops. To bag each small flower for maybe one seed is not an option, so the plant needs to be visited every two days or so.

The post Leucospermum seeds appeared first on How to grow Proteas.