NOTE: The advice below applies to our club’s geographical location and may not apply to your zone. Jacksonville, Florida is primarily in USDA Hardiness Zones 9a and 9b, with the western part of the city in 9a and the eastern part in 9b
January
January is normally our coldest month and a quiet month for bonsai. With cooler weather, water needs will diminish, and trees should be watched to prevent the roots from staying too wet.
Tropical Trees – We shouldn’t be doing any work on tropical trees. Our primary goal this month is protecting trees as temperatures drop below 45 for our most sensitive species (i.e., buttonwood, black olive, etc.) or the low 40’s for other tropical trees. A frozen tropical tree will sustain serious damage that is sometimes fatal.
Deciduous Trees – These species need a winter dormancy period to remain healthy. Once deciduous trees have gone fully dormant it is a good time to do structural pruning since you can see the full winter silhouette and identify potential areas for improvement.
Conifers and Broadleaf Evergreen Trees – These species need a winter dormancy period to remain healthy. It is also time to begin preparing for repotting. Make sure you have the pots, soil, tools, you need once the repotting window begins later in the month.
February
Winter is still upon us in early February even though it doesn’t always feel like it. There have been some cool periods mixed in with some mild Florida temps. A few of my trees got confused and just started to wake up early. Keep an eye on your trees to prevent new growth being damaged during cold nights.
Tropical Trees – We shouldn’t be doing any work on tropical trees. Our primary goal is protecting trees as temperatures drop. A frozen tropical tree will sustain serious damage.
Deciduous Trees – You may have noticed some pollen on your car and flowers on the red maples which indicates spring is close. Your bonsai trees may start showing signs of “waking up” from winter. You will soon see buds beginning to swell and open for spring. That is your sign that the trees balance of energy has moved out of the roots and back into the core of the tree. Once this happens it’s a great time to repot most deciduous trees.
Conifers and Broadleaf Evergreen Trees – These trees can now be safely repotted, trimmed and wired. If you do any real aggressive bending it is a good idea to protect the trees if temperatures drop below freezing. However, protection should
March
The warm days keep coming and our winter should be behind us. Take time to enjoy all the signs of spring around your garden. With a garden full of flowers, fresh green growth, and nice weather it truly is a beautiful time of year.
Deciduous Trees – leaf buds should be swelling or fully opened. They can be repotted any time before the leaves fully emerge. After the leaves start to open its best to wait into next year to repot. Young soft leaves will transpire quite a bit so pay attention to your watering.
Conifers and broadleaf evergreen trees – We are reaching the end of their repotting window now. You can still trim and prune but be careful when wiring certain species (like juniper) as bark can very easily slip from the cambium this time of year.
Tropical Trees – We are getting closer but it’s still not their time yet. You should be busy enough with deciduous that it won’t be a problem to leave them alone for another month.
For all trees keep an eye out for any signs of pests. The new young growth is a tasty treat to all kinds of insects.
April
Now that we are seeing spring temperatures our soil has warmed causing root growth followed by a spring flush on all temperate trees. Tropical trees should be following the same pattern just slightly later, they just require a higher temperature for root growth to initiate.
Deciduous Trees – Spring is fully here and all of your deciduous trees should all be leafed out. Wait to fertilize until after the spring flush has hardened off. For instance, if you look at new maple leaves they will be very soft and have a slight red hue. These leaves have not gotten to the “leather hard” stage where their outer cells harden to prevent excess moisture loss and sunburn.
Broadleaf Evergreens – These can still be repotted but some care must be given if our temperatures raise dramatically. Now is a good time to conduct detail pruning and leaf reduction to lighten the canopy and allow light into interior branches.
Conifers –Their roots should be mostly left alone until fall. Wiring and pruning can still be done.
Tropical Trees – Tropicals should be coming out of the greenhouse. They can be pruned if necessary. It’s still not warm enough to repot them yet with nighttime temps still dropping below the 60’s on occasion. We are getting closer and repotting can probably begin in late April or early May.
For all trees keep an eye out for any signs of pests. The new young growth is a tasty treat to all kinds of insects.
May
TEMPERATURES – The temperatures are moving from warm to hot. Keep a close eye on your plants. They will begin to dry out faster and some will not be able to tolerate Florida’s intense sunlight. Finding locations with afternoon shade will greatly increase the health of many plants. It is also a good idea to water your plants early in the day (when possible) so the leaves will be dry before going into the night hours, decreasing the chance of fungus.
TROPICALS – It is now almost summer and the warm nighttime temp’s means tropical trees are growing again. It’s now safe to start repotting, defoliating, and do major cutbacks on your tropical trees. You can begin to repot your tropicals such as ficus, bougainvillea, and Fukien tea plants. It is still a good idea to wait on the very sensitive trees like buttonwood. Many of your tropical trees will be shedding some interior leaves and pushing new growth. A peek under the soil will show many new white root tips. If your tropical tree haven’t started pushing new growth check it carefully for signs of stress or disease.
PRUNING – You can continue to prune most trees that are still rapidly growing. The removal of branches will encourage new growth. Think of it as addition by subtraction; however, it is important to remember the old axiom think twice and cut once. I have yet to successfully glue a branch back on after it’s been cut off.
MISC – Continue to keep an eye out for any signs of pests o disease. With the cooler nights in late April I have been seeing signs of fungus and minor pest issues continue longer than normal.
June
Now that June has started, we should be entering our rainy season with pop-up afternoon showers commonplace. Tropical trees will love this heat and humidity and their growth will kick into high gear. All your tropical trees can now be repotted, pruned and worked on safely.
TEMPERATURES – Your plants are probably drying out fast and most will need daily watering. Some will not be able to tolerate Florida’s intense sunlight. Finding locations with afternoon shade will greatly increase the health of many plants. Look for signs of heat stress. If the soil is moist and the plant is wilting, especially in late afternoon, this is a sign the plant is stressed. You need to get it out of direct sun. Usually after sunset these plants will “perk up”. Best to keep those plants in dappled sunlight or in shade for a few weeks. Bottom line is check your plants. If the soil is wet, don’t water. Misting the foliage or bench will help to cool things down.
PRUNING – You can continue to prune tropical, broadleaf, and deciduous trees that are rapidly growing. The removal of branches will encourage new growth. For non-tropical I would suggest a lighter approach during the hottest months. Temperate trees are typically under more stress during high temperatures and that should be considered when pruning.
July
We are finally seeing rain, but the last few weeks have been brutally hot and dry. We had some early intense heat that really stressed a lot of plants. I personally experienced leaf burn and other issues on plants that I have never had issues with in the past. Be diligent in looking for signs of heat stress. If the soil is moist and the plant is wilting, especially in late afternoon, this is a sign the plant is stressed. You need to find a new location for it and get it out of direct sun. Usually after sunset these plants will “perk up”. Best to keep those plants in dappled sunlight or in shade for a few weeks. Bottom line is check your plants. If the soil is wet, and you don’t need to water, then misting the foliage or bench will help to cool thing down.
PRUNING – You can continue to prune tropical, broadleaf, and deciduous trees that are rapidly growing. The removal of branches will encourage new growth. For non-tropical I would suggest a lighter approach during the hottest months. Temperate trees are typically under more stress during high temperatures and that should be considered when pruning. All tropical trees can now be safely repotted.
August
Similar to last month, be diligent in looking for signs of heat stress. Stressed plants may benefit from some afternoon shade to reduce the need for transpiration cooling. Heat and humidity is a breeding ground for fungal issues. Consider preventative treatment or be ready at the first signs of an issue. You can continue to prune tropical, broadleaf, and deciduous trees that are rapidly growing. The removal of branches will encourage new growth. For non-tropical I would suggest a lighter approach during the hottest months.
Temperate trees are typically under more stress during high temperatures and that should be considered when pruning. It doesn’t seem like it now but there are only about two months left to repot and do major work on tropical trees. Once we reach the end of September the temperatures will moderate some and the ideal tropical repotting window will have passed.
September
By now the seasonal advice will look very similar to our ongoing summer care. Practices are very similar as we enter the tail end of summer.
1. Your plants might show signs of heat stress. Stressed plants may benefit from some afternoon shade to reduce the need for transpiration cooling.
2. Heat and humidity are a breeding ground for fungal issues. Consider preventative treatment or treat at the first signs of an issue.
3. If you haven’t already now is the time to repot your tropical trees and do any intensive work. Tropical trees prefer about 6 weeks of consistent nighttime temps over 60 degrees to fully recover from any major root work. Now is the time to take care of that work you have been putting off. Once we reach the end of September the nighttime temperatures will moderate some and the ideal tropical repotting window will have passed.
4. For non-tropical I would suggest a lighter approach during the hottest months. Temperate trees are typically under more stress during high temperatures and that should be considered when pruning.
October
October is the month in which we can expect our temperature to moderate and we will get a break from the heat. With cooler night time temperatures we should minimize work on tropical trees. They can still be pruned but it is too late for root work.
October is usually the end of our rainy season. Continue to monitor your bonsai for their watering needs. When you water your bonsai, you will soon notice that some need less water than others. Our days are getting shorter and our temperature cooler, causing some plants to start their period of dormancy. Other plants will still be growing vigorously and should be fed, if needed. At this time of the year, it is wise to use a fertilizer with less nitrogen.
Now is a good time to wire trees that are going dormant. Wire can generally be left on longer now but still needs to be watched as trees put on a lot of their woody tissue (trunk growth) this time of year.
November
November is when we must start thinking about winter preparation. The temperature should still be mild enough that plants will not have to be protected YET but you want to get prepared. My suggestion is that you place your tropical plants in one area so you will not forget any if temperatures drop dramatically. Once night time temperatures hit 45 or below start protecting the most sensitive species (i.e., buttonwood, black olive, etc.) other tropical trees will start needing protection once the temperatures reach the upper 30’s. When in doubt it doesn’t hurt to be conservative.
With cooler weather water needs will diminish and trees should be watched to prevent the roots from staying too wet.
Pruning this time of year should be minimal. Trees shouldn’t be putting on much growth due to a combination of shorter daylight hours and cooler temperatures.
With nicer temperatures it should allow you more time outside just enjoying your collection. If you grow deciduous trees you should also get hints of fall color as well. Spend time enjoying your trees beauty, after all that is why we go to all the effort to grow these tiny trees.
December
December means your winter protection should be in place and the weather should be monitored. Once nighttime temperatures are 45 or below we have to start protecting for our most sensitive species (i.e., buttonwood, black olive, etc.) other tropical trees will start needing protection once the temperatures reach the low 40’s to upper 30’s. When in doubt it does not hurt to be conservative. Trees can be overwintered in a greenhouse, garage, or inside as long as you properly account for changing light levels and temperatures. Some leaf drop will be expected if light levels are altered dramatically. Feel free to reach out to a more experienced member if you have concerns about changes to your trees.
Cold hardy species (i.e. ilex, elm, maple, boxwood, crepe myrtle, pine, juniper, etc.) should remain outside throughout the winter. These species need a winter dormancy period to remain healthy. If you are concerned, setting the plant on the ground and providing some wind protection can provide a little extra piece of mind for these cold hardy trees.
With cooler weather, water needs will diminish and trees should be watched to prevent the roots from staying too wet.
Pruning this time of year should be minimal. Trees should not be putting on much growth due to a combination of shorter daylight hours and cooler temperatures.