Filoli’s planned water conservation measures and recommendations.
Find out what's blooming at Filoli from January to December.
Learn about Filoli plants and gardening practices—ask the experts.
Jazz at Filoli
Our 24th season of talented artists on the Jazz stage.
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.
Week of July 28 – August 3, 2014
No new plantings during the peak of summer beyond the occasional addition to the Cutting Garden as plants become ready.
Plant of the Week:
More and more, we have had to rely on bedding begonias for our summer beds. As the tree canopies around the garden have matured, beds that were mostly full-sun have become partly to mostly shady. For the spring season, this is less of a concern because many of our trees are deciduous and the beds get plenty of sun. In summer, in places like the Chartres, and the dining room terrace, the oaks and other trees are now so large they cast significant shadows throughout the day.
Our summer begonia beds this year are the West Reception, Dining Room Terrace, Chartres, Beds 4 & 5, and the Dutch Garden. Featured varieties are Begonia x benariensis ‘Big Rose with Bronze Leaf’, ‘Big Red with Bronze Leaf’ and ‘Big Red with Green Leaf’, B. semperflorens-cultorum ‘Brandy’ and ‘Whisky’, and B. elatior ‘Charisma Pink’. The ‘Big’ series, ‘Brandy’ and ‘Whisky’ are your standard bedding begonia varieties. The ‘Big’ series is a newer variety that has been bred for increased height. (The ‘Big Red with Broze Leaf’ was used last summer in front of the White House’.) These suit the taller hedges of the West Reception, Beds 4 & 5, and the Dutch. ‘Brandy’ and ‘Whisky’, which are part of the old Cocktail series, is a shorter variety and works well with the lower hedges of the Chartres. ‘Charisma Pink’, which is more of a tuberous variety, we found last year looks best when used in containers. (All our begonia seed was donated for the summer display from Benary Seed Company.)
As with all bedding begonias, they prefer bright, indirect light, but also tolerate considerable shade. Since these plants are succulent, it is better to under rather than to over water as they are prone to rotting in wet conditions. (This is perfect for the 2014 drought!) With cool summer and fall temperatures, begonias will develop powdery mildew on their leaves. Two years ago we encountered severe powdery mildew, but this summer has been fairly warm and we are hoping that the plants will remain healthy this year.
This week we have a second featured plant, and although this tree can be seen in the garden, it does not grow in a public area. In the backyard of the Gardener’s Cottage grow two Japanese pagoda trees (Sophora japonica), whose heads are visible throughout the Panel Garden. A member of the legume or pea family (Fabaceae), trees can attain a height of 100 feet. The large panicles of creamy, pea-shaped flowers form a soft cloud around the canopy. The tree is being featured presently because it is starting to flower and is being noticed by visitors and volunteers alike.
Also known as the Chinese scholar’s tree, it is native to central China and Korea. In the fall, the tree forms 2-3” succulent, pendulous pods, which have swollen points where the seeds are situated. The name scholar’s tree is attributed to the fact that the bumped pods are reminiscent of the beads on an abacus.
All of the summer plantings are well established and filling in nicely. Almost all of the beds are showing nice color. For the next two months, the annual beds should be at their prime. Later in the season, some of the more perennial type plants will carry the garden through the end of the season including the “queens of the fall garden”-- the dahlias.
The hydrangeas are absolutely gorgeous right now. In particular, the bed adjacent to the Walled Garden shop and the southwest corner of the panel garden are laden with blooms. The range of blues and purples just boggles the mind! See the section below for more on the science behind the colors in hydrangeas.
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 spectacular.
Many summer-blooming shrubs and vines are blooming including the Chilean jasmine (Mandevilla laxa), pomegranates, and star jasmine.
The perennial border was recently cut back after its spring bloom. The different varieties will start to re-sprout and fill in over the next month and bloom again after mid-summer.
The annuals and perennials in the Cutting Garden are looking impressive. Some of the best bloomers right now are the snapdragons, Rudbeckia, Godetia, and many others. The historic English lavender is also blooming right now and is creating a lovely backdrop to the garden area.
The Kitchen Garden is really coming alive with the pumpkins, chard, Brussels sprouts, flowers, gourds and lavender. Watch as it continues to fill in and become more and more dramatic through the summer.
The summer hedging of the English laurel hedge should be completed week. This back “wall” to the Panel Garden, which runs the entire length of the area, gets trimmed each summer after its spring flush of growth. With a hedge that is over 500’ in length, this translates into nearly a quarter-mile of total length (both sides) that is trimmed each year!
Notes and Common Questions
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.
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.
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 will be 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, will be at the center, surrounded by the names of the three Roth children: William, Lurline and Berenice. Three benches are being built for the patio, and three large terra cotta containers have been purchased. Construction of the patio should begin in the next month and it is hoped that it will be completed by Mrs. Coonan’s 94th birthday in August.
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