Monthly Archives: February 2010

gardening tips

Microclimates, Rainfall and Pests

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Gardening in our microclimates might be challenging and it’s no different here in Maui. Yes, despite the balmy weather, the rainfall here limits what plants thrive. You can drive 5 minutes from an area that receives 400" of rainfall per year to another spot 10 minutes away that gets only 19" per year. Then drive another 15 minutes and you’re in a desert-like area with annual rainfall of 10" while the east side of the island, in Hana, is getting 83 inches.

Gardeners in Maui in several ways just as we do. One way is to grow the right plant in the right place. For example, at 4000 ft elevation near the volcano, 55,000 lavender plants  of 45 varieties grow happily in rocky soil. Olive trees – brought over from Santa Cruz – dot the fields. Interesting to note that the lavender plants provide a natural pesticide against the ants that invade the protea flowers. Proteas do well here. Reminded me not to miss our spectacular show of proteas  at the UC Arboretum in April and May. If you’ve never walked through this free garden it’s a treat not to be missed.

If you think all the soil here is of volcanic origin, think again. Of the 12 types of soil in the world, 7 different orders occur here.   The state of Hawaii, as a whole, has 11 types, more than any other state in the United States. By comparison, Maine has only 4 types while the Santa Cruz Mountains has a whopping 9 orders just in our little corner of the world.  Yes, folks, that’s right. No wonder gardening can be a challenge where we live.  What thrives up the road from you doesn’t always grow the same in your yard. Knowledge of soil behavior and nutrients is important where ever you garden.

Maui has a native pea, a native coffeeberry and a native huckleberry just as we do.There is even a native hydrangea although the type we are most familiar with was brought over from Japan in 1790.  Mostly, you see flowering plants introduced from other parts of the world.  Since the 1800’s, people have been bringing all types of plants to the island just like early settlers did to our area. Many of the plants that we commonly grow like the Princess flower ( tibouchina ) and strawberry guava are invasive here. Others like blue plumbago bloom in the drier areas and behave themselves. Gardeners here face the same problems as we do and strive not to dilute the native gene pool.

The rain in Maui is distributed throughout the year which is different than our Mediterranean climate. Before you get jealous, though, this allows slugs, white fly and fungus to proliferate year round. I see mealy bug under most of the plumeria leaves. This intoxicatingly fragrant tree is easy to propagate and grows everywhere on the islands. If you get at least 6 hours of hot sun per day and keep them inside or a greenhouse above 50 degrees at night they will bloom even in our area.

I’ve enjoyed my time in Maui but there’s no place like home.

California Native Plants

Redwoods in Maui

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Redwoods in Maui?  I first heard about them at the Nature Center in .  A sign there said they were grown for commercial reasons in Hawaii. So now that I’m here on the island of Maui I just had to see them for myself.

I knew that redwood from our forests was used in the early 1900’s for surfboards. They were tough and durable but also heavy so the boards were redesigned in the 1930’s combining redwood with balsa.  Balsa was hard to get in large quantities so the boards were constructed of both- with balsa at the center and the rails of tougher redwood to strengthen the board.

But how did redwoods come to be planted in Maui?  Like our area that was clear cut in the 1800’s for lumber and to fuel the lime kilns so too the forests of Maui were harvested in the 1700’s.  Sandalwood, exported to China for its fragrant aroma, became the island’s first cash crop. Millions of trees were logged from the mountain forests. The men of the farming class were forced to cut trees, first on the lower slope and then farther up into the mountains, to pay for the chief’s acquisitions of weapons, warships and European imports.  Further damage was done by livestock brought by westerners  – pigs, goats, sheep and especially cattle. 

When the watershed was destroyed, the water disappeared for sugar cane, too. Reforestation started in the 1920’s when nearly two million trees were planted annually.  Fast growing species like redwoods, cedar, sugar pines and eucalyptus were planted to increase the watershed.  While these introduced trees and shrubs prevented catastrophic destruction, they produced sparse forests with fewer species than the complex, multi-layered systems created by native forests.

Fast forward to 2007 when the area was devastated by a wildfire.  Hawaii is not an area that is renewed by fires like California. It destroyed most of the forest. The redwood trees survived however. This area must suit redwoods as it is draped in clouds and fog at 6000 feet and many of the trees planted in the 20’s and 30’s are over 100 feet tall. Now the area is replanted with native trees as well as 57.000 redwood seedlings that received a blessing at planting time.  More redwoods were replanted because they are less prone to spread fire.

So if you’re in Maui up near Haleakala crater in Polipoli State Park check out the quiet, serene Redwood Trail.  Some of the trees probably came from redwood seedlings from our area.

hedges

Mixed Hedges for the Santa Cruz Mtns

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I hear it all too often, "My new neighbor just cut down all the trees and shrubs between our properties and now they can see right into out house. What can I plant? "   Sometimes, the problem is a road or water tank that needs screening.  Maybe you want a well-planned hedge that will also offer needed food and shelter for wildlife and of course, you’d like it to be super low maintenance. Whatever your goal, hedgerows, as the English call them, are endlessly variable. If you’re planning a living fence of contrasting colors and textures, consider these factors.

Many people only think of plants that remain evergreen when they need screening. However, if you use one-third deciduous plants to two-thirds evergreens they will weave together and you won’t be able to tell where one leaves off and another begins. This makes mature hedges secure borders, especially if you throw a few barberries or other prickly plant into the mix.  You’ll also get seasonal interest with fall color and berries for wildlife. 

Pittosporum, photinia and English laurel make great screens and hedges but what other plants can you use that would be beautiful, productive and practical in all seasons?

Many times a screen may start in the sun but end up in mostly shade. For your sunnier spots why not mix in a few dwarf fruit tree for you to enjoy,  ceanothus and Pacific wax myrtle for the birds, barberry for beautiful foliage and fall color, spirea, rockrose, escallonia and quince for their bright flowers and fragrant lilacs for cutting in the spring?  The shadier side can include Oregon grape for fragrant, yellow winter flowers, snowberry for those striking white berries in the fall,  bush anemone, oak-leaf hydrangea, viburnum and native mock orange or philadelphus lewisii for blossoms in the spring.

To keep down maintenance, mulch around your plants and install drip irrigation. there won’t be any pruning to do if you choose plants that grow to the height you want. Mixed hedges appeal to bees, butterflies and songbirds while also providing flowers, berries and color throughout the year for you to enjoy.

How close should you plant a mixed hedge? If you want a quick, thick screen space plane 2-4 feet apart. This gives them room to breathe and develop their own shapes. Fast growing plants can be space 4-5 feet apart and will usually full in within 5 years.

Provide the for the fastest results. By this I mean amending the soil at planting time, mulching, fertilizing several times a year and watering deeply when needed especially during the first three years after planting when young plants put on a lot of growth. Formal hedges are fine for some gardens but think of all the added benefits you’ll get planting a mixed hedge.