This guest post is by Dr Jess Drake. Jess is writing this series in her spare time because she wants to freely share some proactive ways for people to manage the effects of climate change.
I have written about changes to frost with climate change and choosing native plants with purposes in a changing climate (e.g. bush foods, medicine and fibre). But what about non-native fruiting plants? How are they going to deal with climate change?
I have only had one winter in my garden. In that winter I planted 2 pears, 4 apples, a quince, a fig, a blueberry, raspberries, boysenberries and a youngberry. All of these plants need chill – that is a winter – to produce fruit. However, not too much and not at the wrong time (see my frost post for more details). With climate change it isn’t just going to get frostier. It is also going to get drier. If I am only going to have 400-450mm of rain per year, I need to be savvy about planting fruiting plants that can deal with drier conditions.
Temperature is also a factor. A recent study by ANU has found that most parts of Australia, except a small portion of Tasmania, will have no discernible winter by 2050. That means no chill, no cold, no frosts. Without that chill, there are many non-native fruiting plants will struggle to produce fruit. It also means longer and hotter summers which span 6 months of a year. I won’t only have hotter conditions to grow my fruit in, but I will need more water to maintain my plants too.
Climate change not only means more frosts, but eventually it switches over to no frosts at all. Talk about hard on the plants!
With that in mind, how can I plant fruit trees that considers all these changes?
Here are some things I need to consider for planting fruit trees for a climate robust garden:
- They need to be drought tolerant and/or water efficient
- Can deal with hot weather
- Can deal with frosts
- Can produce fruit with or without frost
- Thrive in the soils I have (my soil is a clay)
I feel a bit all over the place here. Hot and cold. Frost and scorching sun. However, we can use diversity and journaling to help us plan adaptation for producing fruit.
Diversity is all about planting species that can deal with a range of conditions. Having lots of different species or varieties means that you are more likely to create a system that is self-sustaining (looks after itself) and resilient (to extreme conditions). Usually we think about diversity when we revegetate the land, but the same can apply to our backyards.
At the moment, pommes and stone-fruit can deal with the frost, and I still have enough water to get them through the summer months. Over time, however, they won’t be able to produce fruit when there is insufficient chill or when the sun is too hot. Even this last summer I heard of apples getting sunburnt in the extreme heat, rendering the crops inedible*.
I have also planted quinces and figs that do not need chill, and actually don’t like frost that much either. The two varieties I have planted originally come from Mediterranean climates that are generally warm and dry, similar to Australia. The fig in particular can manage drier clay soils, and does not like waterlogging, and needs heat for fruiting – figs may be a winner, as long as you protect them from frosts for the first couple of years of their lives. Of the fruit trees I planted last winter, the fig and quince have done the best so far – they have grown the most.
I have also been thinking about Australian native species. In my first post in this series I talked about the climate being more like Dubbo. I can plant fruiting native species that can live in semi-arid and arid Australia. Some examples include:
· Bush tomatoes, of which there are over 100 species, and the edible ones can deal with extreme dry and wet conditions
· Desert lime, which is cold, heat and drought tolerant
· Gumbi Gumbi/Native apricot, found in drier parts of Australia
· Passionberry, from central Australia
· Quandong, found in drier areas and even Dubbo!
· Native fig, from rocky parts of central Australia
· Bush plum, from central Australia
It seems like I have lots of native fruit options. I just have to find them and hope they like my soil!!
If I have a mix of species, native and non-native, some will do better some years compared to others. Some may die as the climate shifts. I can see what thrives and focus on replanting those species. Having a plant and climate journal is an important part of adapting to changes in climate.
Climate and plant journal
My mother-in-law has a climate and plant journal that is over 20 years old. She records rainfall, when she picked the first Gravenstein apple each year, what was doing well and what was not etc. This helped her decide what was worth pursuing on their farm and what was not worth trying again. I want to do the same with climate adaptation.
Because everyone’s conditions are different there is no one hard and fast rule to planting for climate change. We all have different soils, microclimate, management, preferences etc. We also don’t know exactly how climate change is going to affect our own backyard (yes, there are models, but they only predict across large areas). If we collect our own data we can review it to make decisions that are best for our own circumstances.
As a suggestion for a journal, each month record the following:
· What fruit did you pick, when and how many kg
· Number of frosts
· Number of days over 35*C
· Soil conditions – wet, dry, hard, worms present etc.
· Any noticeable plant health or disease issues
· Watering, mulching and fertiliser regime
Having this data allows you to ask about plant health and changes in climate. If you are seeing noticeable patterns, like your apples keep getting burnt, or frosts are starting to stop, then it may be time to adapt! Fruit trees can last many years, so you may start seeing slow changes with climate over time. Try growing something different or see what you have recorded that is doing well and plant more things like it.
We can plant fruit trees now for climate change in the future by thinking about the climate to come, and choosing a diversity of plants. We can also record our successes and failures to work out what is working well as our climate shifts. Plants take a long time to establish, so starting to think about it now helps with success for the future.
To find out more about how to grow amazing and diverse fruit, I suggest the knowledgeable Grow Great Fruit.
*You could consider shading your fruit if you have access to appropriate materials.