"Gardening experiments"

We can learn much about gardening by trying different methods.
Sunday, 13 June 2021        

Azaleas may benefit from tea leaves?

Leafing through some gardening books given to me a few months ago by a friend's mother, who had moved into retirement accommodation, I came across a slip of paper upon which had been typed some 'handy tips'. 'Pour tea leaves from the teapot around azaleas - tends to make soil acidic', read one. Another stated: 'Vegemite mixed with water poured on cuttings will make them strike better'. I smiled as I read the hints: I love this sort of gardening lore and it reminds me that whilst horticulture is a science, home gardening is a complex mix of science, art and folklore, which is what, to me, makes it so alluring.

In recent times, I have had a yearning to empirically test some of the gardening rules I have lived by for so long without ever questioning them. I'd like to set up some simple experiments to test the efficacy of various suggested ways I've heard over the years to promote the striking of cuttings, for example, by setting up a series of pots with the same cuttings and different ways of treating them: with the 'Vegemite water' mentioned above, or dipping the ends in honey, or using hormone powder, or watering the propagating mix with a seaweed solution, and see which lot of cuttings strikes the most successfully. I haven't actually got round to doing such an experiment yet, but I have been trialling some other gardening practices in recent times, particularly the timing of pruning various plants in the garden and observing the results.

Last year, for instance, I took what was, for me, a big risk and pruned many of my smaller Salvia plants (such as Salvia microphylla, Salvia x jamensis and the 'Wish' Salvia series) in late May, rather than in mid-August, which I had been doing for more than 30 years, ever since I started growing Salvia. This new regimen was on the advice of a friend, whose Salvia plants always looked much more advanced than mine in late spring, flowering way earlier than mine. Despite some apprehension on my part, the experiment was a success, and I was amazed how much growth occurred on the plants during winter, a time when I thought nothing happened. Also, my garden looked a lot neater (if barer) with those plants cut back much earlier. I realised that my August pruning (which I still do for more cold-sensitive plants as cutting back earlier can actually be detrimental!) was due to my blindly following a pruning regime that was inappropriate, and probably based on that of my mother, who lived in a much cooler climate than I do.

I've also since cut back other plants at different times and observed the results, despite my fears that I might kill them. I have learned that the irrepressible seaside daisy (Erigeron karvinskianus) can be cut back both in autumn and in midsummer and it will come back better than ever. I also cut back my Plectranthus and Lantana cultivars hard in late May last year, and found they grew back very well. Very tall autumn- and winter-flowering Salvia can be cut back very hard after flowering as well as in early January to maintain some control over their height without compromising blooming. I also learned from a friend that Fuchsia should be pruned in July in Sydney, not in September, which I had always done, and following this suggestion, my plants were so much better. Note that in areas of Sydney where frosts are experienced, it is better to leave much pruning till all risks of frost is over as any new growth that occurs after pruning in winter, may be badly affected by a cold snap.

Another form of experimentation I have been playing with is to do with epiphytic plants. I have never really understood these plants very well and struggled to grow many of them properly until I started to attach them to my epiphytic stump. Many but not all orchids, ferns, hoyas and bromeliads are epiphytic, so it has been a case of trial and error to see which plants stick - literally - to the stump with their roots. I do attach them first with a handful of orchid bark in a stocking tied onto the stump or tucked into the chicken wire I have wrapped around it. An exciting recent discovery has been the emergence of what I hope is a flowering spike on the moth orchid (Phalaenopsis cultivar) that I attached to the stump some months ago. I had been given this plant as a birthday gift several years ago and had kept it in a pot in the garden since. It had never reflowered in its pot, but I decided to give it a chance on the stump rather than toss it on the compost heap. I don't know if Sydney's winter is going to be too cold for it, but it is thrilling to watch the progress of the experiment.

Pushing the boundaries of climate is something I have been doing - mostly unsuccessfully - since I began gardening 40 years ago. Originally, I didn't know this was what I was doing, as I thought that I could grow anything I liked in my Sydney garden, having no idea that plants from different parts of the world needed certain conditions to thrive. Many tears were shed as a multitude of beautiful cold-climate plants met their demise at my hands in those early years. Eventually, I twigged at what was going on and started to choose plants from warm climates more similar to Sydney: South Africa, South America, Mexico, Southern China and other parts of Asia. Later on, I tried to see whether truly tropical plants would grow in my garden without winter protection - in general, they didn't, but I wanted to kill them myself to be sure, rather than taking someone else's word for it! Sometimes we are able to find a microclimate in our garden that suits a plant that is outside its climate range. The few plants that do happen to flourish in our climate when they theoretically shouldn't, are much treasured in my garden!

In reality, gardening is one long experiment - a single-case study, to be sure but intriguing and revealing: we can learn so much by varying the way we do things; trying new plants; testing plants in different parts of the garden to see if a sun-lover can take a bit more shade, for example; seeing if a so-called annual plant can survive through winter, as I found was the case some years ago for Salvia splendens, which in reality, I discovered, is a perennial . I find it is so important to keep records of what I do in the garden so I can later evaluate the results of my trials, otherwise I completely forget all about them!

I'd love to hear what you have learned through gardening experiments!


 Reader Comments

1/6  Margaret - 2122 (Zone:10 - Warm Temperate) Monday, 14 June 2021

Great blog, Deirdre! I enjoy reading about gardening experiments tried by other people. I do find using a seaweed product when striking cuttings does work. I have tried honey and vegemite, without success. Among begonia friends, cinnamon is recommended as a cure for mildew. Tried it, did work, but is an expensive cure, and did leave the foliage brownish! Thanks for letting us know the results of your experiments! I do think seaweed helps with cuttings! Deirdre


2/6  Kerrie - 2104 (Zone:10 - Warm Temperate) Monday, 14 June 2021

I've found here on Pittwater nestled between the bay & the ocean the winters are far less harsh on plants in my garden & I've been able to grow tropical plants that usually only do well from Byron Bay up. Yes you have a great microclimate there! Deirdre


3/6  Ron - 2110 (Zone:10 - Warm Temperate) Monday, 14 June 2021

Gardening is the same as medical practice, the application of science and art and a bit of folklore thrown in! Ron I think a lot of things are a combination of these three! Deirdre


4/6  Sue t. - 2566 (Zone:10 - Warm Temperate) Monday, 14 June 2021

Your tips bring back the memory of my grandmother's beautiful blue Hydrangea that grew just outside the back door. She always emptied the teapot under it to keep the flowers blue. Might try some cuttings with vegemite water and then see how they do. Of course I'd need a control as well and i can see this rapidly running out of control. I like the idea of the tea leaves on the hydrangea. I rather like the idea of doing some experiments on striking cuttings with different preparations added but I need to be more organised to set them up! Deirdre


5/6  Leveena - 2099 (Zone:10 - Warm Temperate) Tuesday, 15 June 2021

I have noticed over the years that I have been able to grow tropicals (Curl Curl-northern beaches Sydney) which 15 years ago were out of the question. I have a thriving grove of spiral ginger in a sheltered spot under a tree canopy. I couldn't even buy these in Sydney 15 years ago! That is great. My garden used to have frosts when we came here 27 years ago but haven't had any for a few years now. Deirdre


6/6  Jessica - 2076 (Zone:10 - Warm Temperate) Wednesday, 16 June 2021

May I ask how you keep your records, Deirdre? I'm just beginning to create a spreadsheet with months across the top and plants down the side. When I add a new plant to my garden, I'll fill in when any tasks associated with that plant should be done, and I'll add any relevant notes. Does that sound like the right approach? It sounds very organised to me! I have never been very systematic with records. I started an index card system once for plants but I didn't keep on with it. I wrote down lots of things in garden journals, where I stuck plant labels. It was all very haphazard! In the end, creating the website plant reference was a way of collating all the information on plants I grow and the 'jobs to do' a reminder to myself of when to do what. Your idea sounds great - maybe you could group plants of a similar type together - evergreen shrubs, deciduous shrubs, perennials, bulbs etc as that may help find common themes in when to do tasks - for example, most deciduous flowering shrubs are best pruned straight after flowering - which could be helpful for planning your gardening work. Eventually it does sort of become second nature but I still sometimes forget to do jobs! Deirdre


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