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What's Blooming

More Information
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Drought Response

Filoli’s planned water conservation measures and recommendations.

Blooming Calendar
Blooming Calendar

Find out what's blooming at Filoli from January to December.

Garden Information

Learn about Filoli plants and gardening practices—ask the experts.

Autumn at Filoli Festival

Saturday, Sept. 27 is the day for family fun.

Plant Highlights This Week

Flowers are one of the most pronounced markers of the progression of time in a garden. Each month we scout the Garden for amazing blooms and feature our favorites here. Check back often to see what we have in store for your next visit to Filoli.

New boxwood plants surrounding the Garden House beds.
The completed Roth Patio.
The pumpkins are sizing up in the Kitchen Garden.
The gourd house in the Kitchen Garden also looking very bountiful.

Garden Happenings
Week of September 15 - 21, 2014

New Plantings:
We have Garden House beds partly because the zinnias were crashing, but also because we are replacing the old, overgrown boxwood hedge with new plants. Over the decades, the hedge has grown beyond their original line, and has become incredibly woody. We’ve been propagating and growing boxwood the past two years for this project. Since we are not going to be doing any lawn renovations this summer-fall, we felt now is a good time to renovate these beds. Hopefully the project will be completed in the next week. Next, we will move on to replacing some of the hedges in the Dutch Garden.

Plant of the Week:
Last Friday, the new teak benches arrived from Weatherend Furniture in Rockland, Maine for the new Roth Patio. These are beautiful, beautifully made, custom benches that surround the center medallion in the patio. Be sure to visit this new installation next time you are visiting the garden.

Although not a plant we grow, obviously, I thought I’d talk a little bit about teak wood and trees. Tectona grandis is a member of the Mint Family (formerly in the Verbena Family) native to south and southeastern Asia. They are large trees to 120 feet that are deciduous in the dry season. Teak produces fragrant, white flowers. Its leaves are edible and are used in specific recipes made in India and Indonesia.

The natural oils in its wood make it highly resistant to termites and other decaying organisms, hence its extensive use for outdoor furniture and other outdoor uses, including boat decks. The wood also has considerable silica in it, which contributes to its durability, but also quickly dulls tools used to cut and shape it. Plantations occur throughout the tropics, but particularly in Southeast Asia, Equatorial Africa and and increasingly in Central and South America.


As gardens age, we are forced to respond to woody plants that are facing the end of their road. The latest tree of concern in the garden is the stately oak between the Dutch Garden and the Walled Garden lattice area, home of the purple, blue and white hydrangeas. The vigor of this old, coast live oak (Quercus agrifolia) has been decreasing for at least a decade and over the past few years has been displaying some significant disease issues and has reached the point where we are very concerned.

Most recently, a large fungal growth arose from the base of the tree on the east (Dutch) side. This organism is called weeping conk (Inonotus dryadeus), and like the more common shelf conk (Ganoderma applanatum), is an indication of root and buttress rot. Prior to this, large clumps of oak root fungus (Armillaria mellea) have grown from the west (hydrangea) side of the trunk. And on top of this, where the two major scaffold branches arise from the trunk, there is an accumulation of soil and other debris at this crotch, which often is indicative of a lack of solid structure.

We plan to undertake further investigative work to thoroughly validate the problems. With this triumvirate of serious issues, the outlook is not good. At the very least, we will plan to heavily reduce the weight of the north scaffold branch, which is the more weakly attached, to reduce its weight.

There is a strong possibility that the tree may need to be removed. Removal will be a significant job and come at a significant cost, since all the wood will have to be cut up small enough to haul out of the garden through the garden gates. It will also mean that this part of the garden won’t be in 100% shade anymore. Fortunately, there are other large trees (southern magnolia, New Zealand black beech) around the tree that will continue to shade many of the plants.

Update: We had a second arborist look at the oak tree last Friday. Jim McClenahan, our primary large tree work provider, recommended Deborah Ellis, who came out for a consultation. One of Deborah’s services is providing tomographic scanning. Tomography is a process using sound wave scans to assess the state of the interior of the base and trunk of the tree. We hope to have the scan done this week, which will help us to better understand the state of our oak tree. The tomography scan will be happening on September 22.

Plant Highlights:

Roses-Roses-Roses!  The Rose Garden continues to delight. In most years, the rose plants seem to pause around early summer. This year, while some plants are taking a break, many of the roses continue to bloom and look very nice.

Many summer-blooming shrubs and vines are blooming including the Chilean jasmine (Mandevilla laxa), silver lace vine (Fallopia baldschuanica), and pomegranates.

The Kitchen Garden is looking quite bountiful right now. The pumpkins are quite large, tomatoes and peppers are fruiting, purple cabbages are making heads and gourds are beginning to hang from the gourd house.

The annuals and perennials in the Cutting Garden are looking impressive. Some of the best bloomers right now are the grasses, broom corn, zinnias, Rudbeckia, swan plant, and many others. The herbaceous peony plants have taken on their lovely fall color, which is one of my favorite elements to Filoil’s late season garden.

Garden Projects:
Fruit picking continues every week as we approach the Autumn Event. In these last couple weeks before the event, we are picking some of the last apples for tasting.

As of now, we have sent two deliveries of fruit to Hurley Farms in Napa for our jam project. The first jars came back recently. Look for an opportunity to taste and buy apple and pear butter at the Autumn Event.

The topiary olive trees in the Sunken Area are being somewhat renovated to make them more manageable. Our plan right now is to shape them somewhat more loosely, rather than the tight sides and top. This should result in a more sustainable ability to maintain these trees.

Notes and Common Questions

  • Olive Renovation
    Another tree that has been in decline is the olive across from the Lock and Key sculpture near the front drive. The top of the canopy was mostly dead, probably from Verticillium wilt, while the lower trunk and roots were still quite vigorous. Olive trees are good candidates for renovation when they are too vigorous or lack vigor and this technique of cutting the tree back to six feet is often employed in orchard management. Our plan is to retrain the sprouts that emerge into a new, healthy canopy. The fencing added around the tree is to keep the deer from eating the sprouts as they emerge.

    Southern Magnolia
    A plant the horticulturists, and volunteers as well, are being asked about recently, concerns the stunning southern magnolia (Magnolia grandifloria) guests encounter as they approach the house and garden from the Visitor’s Center. This magnolia, one in the collection of magnolias added to the front of the house by Mrs. Roth, often introduces visitors to the high horticultural standards for which our gardens are known. (I can still remember seeing the tree when I visited Filoli for the first time on a rainy, spring day in 1994.)  The question is in regard to the thinning canopy on the southeast side of the tree. The branches are not as full and the color is a bit off from the rest of the tree.

    The short answer is that we are still unsure what is causing the lack of vigor. We had wood samples tested from the top of the canopy, and nothing came back conclusive. Visually, the condition looks more like a Verticillium wilt, but none of the samples showed it was this fungal pathogen. We also had the roots tested, which showed Phyophthora, a root rot fungus, but this is common in our soils, and would show symptoms throughout the canopy.

    Recommendations we’re received, and the actions we are taking include giving the tree supplemental water through the summer and composting under the canopy. We’ve increased the water the past few weeks and plan to mulch with 4” of compost in the coming months. We’re hopeful that with some TLC the tree will grow out of the condition and begin to fill back in over time.

    Drought Update
    The Filoli drought page is on our website (http://www.filoli.org/drought/). As many have noted upon visiting this summer, many of our lower-profile lawns are somewhat to completely brown. We’ve also reduced our water use in our orchards and any other woody plantings by approximately 40%. We felt that these two major reductions in irrigation use would be the best ways we could do our part in conserving water along with everyone else in California. At this mid-year point, Dave Herrington, head of our maintenance team, reports that we have reduced our total water use by over 55% over last year!  Considering that last year was the driest calendar year on record, and that we had no conservation plan in place, with our use up approximately 25%, the outstanding savings this year might be somewhat inflated. That said, looking back to 2012, we’re still probably saving 45-50% over a typical rain year.

    “New” Garden Room
    When Mrs. Berenice Spalding, one of the Roth twins, passed away last year, a bequest was made to Filoli on her behalf. Mrs. Spalding wanted her donation to be used on lasting improvements to the house and/or garden. Cynthia approached Board member Denise Bates (daughter of Lurline Coonan) with the concept of a garden space honoring the Roth Children. Filoli staff and the governing board agreed that a new seating patio under the persimmon tree in the Rose Garden was the best fit. Denise, who is a landscape architect, designed the new patio. The rectangular patio surrounding the persimmon tree has been laid with two patterns of brick separated by a frame of bluestone. In the center of the patio, a medallion with FI-LO-LI, like the one above the Filoli Gate, is at the center, surrounded by the names of the three Roth children: William, Lurline and Berenice. The patio is now complete and the accompanying flower containers are in place. The benches arrived last week.

    The Colors of Hydrangeas
    In the wild, Hydrangea macrophylla, which is native to Japan, has pink flowers. Over the last century, different cultivars (cultivated varieties) have been bred to have darker pink, blue, or white flowers. To understand color change in hydrangea flowers, we have to delve into some basic chemistry. Hydrangeas prefer a slightly acid soil (pH 6.0-6.2). At this pH, hydrangeas will maintain their original color. As the soil approaches neutrality, and then becomes alkaline (above pH 7.0), and aluminum becomes less available to the plant, and thus, the pinks will become darker pink and the lighter blue shade will turn pink. In acid soils (lower pH), the pink flowers will become blue and the pale blue will become dark blue or purple. The exact shade of blue depends on the original color, how acidic the soil is and how much aluminum is available to the plant. White flowers will not change color with changes in soil chemistry.

    At Filoli, to acidify our soil and enhance the color of our blue hydrangeas, we add one-quarter to one-half pound of granular aluminum sulfate around the base of each large plant in November. If your soil is in the neutral range, it is fairly easy with the addition of aluminum sulfate to enhance the blue color in hydrangeas. It is much more difficult to achieve an alkaline soil, but this can be done by adding dolomitic lime several times a year around your plants. If your soil naturally runs acid or alkaline, it can be extremely difficult to sway your soil to the opposite end of the spectrum.

    For more information on Filoli’s hydrangea care, please see the Garden Resource Center page of the Filoli website (http://www.filoli.org/garden-reference/). Here you will find a reference sheet on hydrangea care, many other Filoli plants, as well as other garden maintenance situations.

    Bloomin' Bucks Program
    Whenever visitors, volunteers or anyone else asks about where Filoli purchases our bulbs, after telling them that the bulk of our bulbs are purchased wholesale from the Netherlands, I tell them the best retail vendor in the US that I know is Brent and Becky’s Bulbs. Brent Heath’s family has long been in the bulb business and because of their lasting relationships with the Dutch growers, Brent and Becky are able to sell top quality bulbs. If Filoli could afford to buy all of their bulbs from this company, we would.

    As part of the company’s commitment to public gardens, schools and other non-profits, Brent and Becky established the Bloomin’ Bucks program. With each purchase from Brent and Becky’s through the program, the designated non-profit receives 25% of the funds. Filoli is a participant in this program. So, if you’re planning to order bulbs this year, and like Brent and Becky’s products, please go to the Bloomin’ Bucks page (www.bloominbucks.com) to start your purchase by choosing Filoli as your non-profit of choice. From there, you will be sent to the regular Brent and Becky’s Bulbs website to start your shopping.


Written by Jim Salyards, Filoli's Manager of Horticultural Collections and Education, and Internship Program Coordinator