How to Grow Plants in Hawaii
In Hawaii our beautiful weather turns out to be our biggest challenge as gardeners.
We live in an area where the growing season never stops it is always on. Many of the showy perennials we try to grow simply flower themselves to death in our Tropical Paradise. There really is no Spring Flush or Summer Peak or Fall Ripening or Winter Dormancy. The growing clock is set to full on all the time.
And so the trick here is to keep plants in active growth and to not let, or a least delay, the plants Summer Peak of flowering. If we can achieve this than the active growth surge can continue for a much longer time. We learn one trick from observing the growth cycle of Annuals. In one season they rise from seed, develop full crowns, burst into glorious flowers, set seed and then pass on. If you remove the seeds before they mature you extend the flowering period. You cannot stop an Annuals cycle, but you can extend it.
So with Perennials the first trick is to deadhead your plants. It takes a lot of energy to develop seed. If you remove the seed the plant can then use the energy elsewhere.
But with perennials deadheading alone is not enough to keep the plants in vigorous growth. This leads us to the most important trick for successful perennial growing in Hawaii. And I call this trick CUT AND FEED.
PRUNING YOUR PLANTS
Cut and feed is my mantra. This is the key to gardening success in Hawaii; the unrelenting growing season requires it. And the best time to prune back your plants is when they still look good. Most people wait to long; they wait until the plant is failing and looks poorly. Then they throw fertilizer at it, hoping for a miracle of new growth. But when the plant is failing or has stopped blooming it is much harder to bring them back to health. So the best time to cut back is just after peak flowering, when the plant is still healthy and strong. They will come back quickly and reward you for your work.
Pruning your plants can also be a great way to combat disease. When mildew ruins the leaves or Japanese Beatles shred them, cutting them back (and also feeding them) is a good way to go. For example, Daylilies are subject to rust, a fungal disease. When this happens cut them hard to the ground and feed them. They will bounce back quickly and send up fresh new leaves and gorgeous flowers. Salvias grow so fast that they can get leggy. Prune them back and feed them and they will get fuller and lusher and even more blooms will come. Roses get every disease. Cut them back, remove all the bad leaves and feed them. They will also come back quickly and shower you with flowers.
FEEDING YOUR PLANTS
After plants are cut back and pruned it is time to feed them. When I had my retail nursery customers always asked 2 questions. Should I fertilize my plants and then what kind of fertilizer should I use. I answered with a question of my own. How often do you like to eat, is it everyday or once a month? And of course we all like to eat everyday, and plants are really no different. Giving your plants a little nutrition as frequently as possible is the best way to go. Many wholesale nurseries that produce plants for your garden centers use a system call Constant Liquid Feed. Here, via a fertilizer injector, a small amount of fertilizer is added to their watering lines all the time. So the plants get food every time they get watered. In my current nursery I apply slow release fertilizer to my pots and when watering this slowly becomes available to the plants. A fertilizer injector is usually not practical for the homeowner, but slow release products are readily available.
Another way is to use a liquid fertilizer. When you do this it is best to use no more than 1/2 strength, but do this as frequently as possible. Think about eating only once a month, you wouldn’t do very well. It’s really important to feed your plants, they will respond with flowers if you do.
WHAT FERTILIZER TO USE
But then the question is what kind of fertilizer should I use. And honestly I think that the kind or brand is not that important. What’s important is that you give them something. Additionally the ratio of nutrients, the NPK (nitrogen, phosphorus, potassium), is generally not that important. (Now there are exceptions, like growing Orchids in bark, where a high nitrogen does help.) Again what’s important is to give them something. Now I must admit that I do have a favorite and this is a product with an NPK of around 14-4-9. These low P (phosphorus) fertilizers are often called Palm fertilizers, but I started using them not because I was growing Palms but because I was growing many Australian plants that really resent higher levels of phosphorus. And it turned out that all the plants that I grew (not just the Australians) did well with this NPK ratio. So I use the same fertilizer for everything.
And so I come back to my mantra CUT AND FEED. It’s the key to success in your garden.