Garden tips for April | April 20, 2012 | Palo Alto Weekly | Palo Alto Online |

Palo Alto Weekly

Real Estate - April 20, 2012

Garden tips for April

Advice on pruning, and things learned at the garden show

by Jack McKinnon

I attended and spoke at the San Francisco Flower and Garden show last month and what a great show it was. My talk was on the basics of pruning and the audience had several questions that might seem obvious but for many are not that clear.

Here are some of the questions and my answers. I will also give you some heads ups about what I saw at the show that is refreshing.

1. When is the best time to prune? When the plant needs pruning, prune it. Prune dead, dying and diseased branches any time of the year. The reason this is important is that dead, dying and diseased branches compromise the health and the appearance of your plants. There is no particular season that is best for being healthy or beautiful. Like us, all-year-around is the right time to give the best show.

2. Should I paint the cuts on a tree after I prune it? What arborists have learned is that the tree (or shrub) when it is cut will shrink the cells where the wound took place. In some trees like conifers and Japanese maples there may be some leaking of sap for a while but this is actually good because it flushes the wound of spores and bacteria that may compromise it. Leave fresh cuts to dry without painting them and they will heal better than if they have a moisture-retaining paint job allowing fungus and bacterial growth under the wound.

3. How do I know when to stop pruning? Make a pile of the branches and leaves you remove while pruning and when you have removed 25 to 30 percent of the plant material, it is time to stop pruning. This reduces shock and sucker growth. If it takes two or three years to get the final shape you want, don't worry about it. You are still young, and there is plenty of time to do it over two or three years.

4. How do I sharpen my pruning shears and saw? For the most part, unless you are doing a lot of pruning you don't need to sharpen your shears more than once a year. I use a diamond sharpener made by Eze-lap (, but you can use a diamond nail file just as well. If you want to get persnickety about it then get a good ceramic stone to finish polish after using the diamond sharpener. The test for a sharp shear is by cutting a leaf. If it cuts clean, stop sharpening. As for sharpening saws, I don't bother any more. A pruning saw with Japanese-style teeth (I like Fiskars and Corona saws) doesn't need sharpening. I have been using the same ones for 10 years and aside from bending them (not recommended) I haven't had to do any maintenance at all.

5. What about pruning fruit trees and roses? Fruit trees and roses are pruned differently than ornamentals. This requires demonstration and practice. It is not difficult, but one can really mess it up if you don't know what you are doing.

6. I met a blacksmith who makes hand tools at the show and bought a dibble (for planting bulbs) from him. It is made out of black walnut and is a work of art. What a great line of tools. He makes trowels, cultivating rakes, diggers, a weeder and various hand plows with turned handles and forged blades. They look rough but will last and do a good job. Check out Fisher Blacksmithing at

7. What people can do with plants is truly amazing. The bonsai display was incredible at the Garden Show this year. To be able to take a small tree and keep it small all the while shaping it, trimming it, re-potting and carefully nurturing it for 10, 20, 30 or more years is truly a high art. It combines patience, craft, skill and knowledge in a living art form that can give enormous pleasure in a very small space. I have one Japanese maple that I attempt to make beautiful each year when the leaves come out. I don't know why it hasn't given up on me yet (it has been more than 10 years) but the relationship continues and I am a better person for it.

8. There were more succulents used in this year's show gardens and in the sales hall than I have ever seen before. Vertical walls of succulents demonstrated a painting-like effect in living, drought-tolerant and low-maintenance form and function. It will be interesting to see if this trend continues and where it will go.

9. Growing your own food is taking on new and different forms. One demonstration of hydroponic vertical gardening was presented by Gwen O'Neill. Her blog is and has her pretty amazing story of growing vegetables in a water tower.

10. Edibles are being included in landscape design more and more. Good design makes us happy when we come home from work or when we have guests over, but there is nothing like going out into your front yard, picking a salad and serving it to your family for freshness you can seldom find in even the best restaurants.

Good gardening.

Garden coach Jack McKinnon can be reached at 650-455-0687 (cell), by email at Visit his website at


There are no comments yet for this post