Oceanside Garden

Growing Season

The USDA plant hardiness zones provide a very important piece of information to gardeners – how cold can the weather get without killing my plant. But this only touches on the tip of the iceberg. For many plants, even the USDA zone information needs to be modified by how wet it is at the time of the cold. For example, many plants will survive cold so long as they are relatively dry. Give them cold and wet and they will die.

Some plants will also provide an upper range in which plants can be grown. It is not uncommon to see a plant specified as zones 5 to 9. This is not really very useful at all. It is trying to convey that some plants cannot take excessive heat, or humidity or both. But hardiness zones and heat are not correlated for much of the country.

Mediterranean Climate

The biggest exception is the entirety of the West Coast (California through to British Columbia) where the Pacific Ocean has a huge influence on both the highs and the lows. The ocean provides an enormous stability. In winter we don’t get very cold, and in summer we don’t get very hot. Go inland just a few miles and things can be very different.

The previous paragraph contains an innocuous statement ‘in summer we don’t get very hot.’ That is one of the biggest impediments to what I can successfully grow here at Oceanside Garden. Many plants will remain dormant until the soil or the air have warmed up enough to spur them into growth. There is one plant I was trying to grow – Bauhinia purpurea, the purple orchid tree. It is a delight and would have been perfect except for one small problem.

Last year, the Bauhinia didn’t even break bud until August. It sent out one new shoot that grew to be three inches long and had seven leaves on it. When talking about a tree and with that kind of growth rate it is going to take a very long time to reach a decent stature. Plus, it is unlikely that it would ever set flower buds or that they would ever get to open before cold weather came in.

Unfortunately, that tree will be going on the compost heap in spring and a replacement found.

Death by Heat

To deal with this issue, a number of alternatives have been suggested. One comes from the American Horticultural Society that defines heat zones. They divide the country up into 12 zones based on the number of days temperatures rise above 86F (30C). For us that is almost never and thus we are zone 1. Zone 12 is for areas where this happens more than 210 days a year. Again, this is not useful because it defines when things will die and being in Zone 1, that means that nothing will ever die from heat here.

We have similar problems with tomatoes, which grow so slowly here that they often do not ripen. We need something that tells us about the temperature below which the plant will not fully function. For example, I have seen orchids often being described as sulking below 50F. Thankfully, I have a little space available in the greenhouse over summer and so there is room for a plant or two. I have even successfully grown plants over winter and had ripened fruit in March.

First and Last

Another useful piece of information is the average first and last frost dates. This can help knowing the length of the growing season – at least for plants that are willing to grow at temperatures barely above freezing. But these are averages. If you live by those, you may not take advantage of all of the growing season. Most people tend to stretch a little and cross their fingers.

Sunset attempted to fix all of these issues, at least for the West Coast. They divided the region into zones that consider the total climate: length of growing season, timing and amount of rainfall, winter lows, summer highs, wind, and humidity. This works for well-known plants that have been trialed in a lot of places, but growing members of the Protea family is still restricted to a few of us adventurous types. Let’s face it, nobody really knows much about how well they can grow in this country.

Lack of Data

The lack of heat is a concern for a number of the plants. There is little information on the Internet about the amount of heat they need to set flower buds. A few locations suggest they need temperatures higher than we get. So far, they appear to be wrong. A number of plants have bloomed, but I think the right question may be – do they bloom as well as they might in a warmer climate? I am OK with that. Part of the reason for wanting to try some of these plants is because we are in a warming climate and many native trees and shrubs are beginning to suffer.

This summer, the forests looked quite sad with a brown tinge over their normally bright green coats. It takes time for new trees to settle and become established. Just like many of the English gardeners – they planted for the future, not for today. Many of what are considered the great garden landscapes took 100 years to reach a modicum of maturity. We would not have had them if the gardeners of the time had not thought about planting for future generations and not for instant gratification.

Can I say I am planting a garden for the next hundred years? Perhaps not, but I do have a longer term view than most people.

Calendar

Gardener’s Log – December 2021

Oh, what a month. To say that this has been a wild weather month is no exaggeration (see below for the averages).

California excursion

The month started off great, with our second trip down to California this year. The main reason for this trip was conference but then we also visited three University of California locations that have arboretums or botanical gardens (Santa Cruz, Berkeley, Davis) and the Ruth Bancroft Garden in Walnut Creek.

This was actually from our trip in February, but in December it was just as packed.

We had 40 new plants crammed into our car, but then impending bad weather all the way from the Bay Area up the coast made us cut the trip short. Fearing that the mountain pass would become treacherous, we assessed coming up the more coastal US101, but there were reports about road closures due to landslides. Instead, we took a chance on I5 and the snowy pass. Chains were purchased, although in the end not needed.

Christmas Un-Presents

Then came Christmas and Oceanside Oregon got a white Christmas. Most of it was hail, but there was also some snow mixed in. More arrived on Boxing Day (that’s the day after Christmas to us English folks) and some disagreement on the weather forecasting models had us dreading temps in the teens – unheard off for us. Temperatures have only touched 32 a couple times in the 6 years that we have lived here.

We crammed as many plants as we could into the greenhouse which has a small heater, but there was not room for everything and we had to be selective. There were some wrong choices, or perhaps better put, we did not have enough knowledge about some of the plants to know their tenderness.

Thankfully, we only dropped to 29 that night, and all of the later threats of cold – well evaporated. Even that has brought some heartbreak. It is now evident that we are not in zone 10 as we were beginning to assume. Some plants are clearly suffering or have died, and we may not know the full impact for some time. Still – gardening has always been about pushing limits and trying new things so we expect to have some failures.

Weather Summary

It certainly was a cold, wet December compared to last year. On average we were almost 5 F colder. We also had 5″ more rain, the total this year being over 17″. The setup for the cold over Christmas was a weather pattern we had not seen before. Thankfully, it did not turn out to be as bad as the models predicted, but it has still resulted in some plant losses. Time will tell if any of them re-sprout in Spring. Until then – here is hoping that 2022 is a great year for the garden and all gardener’s out there!

What happened in Oceanside Garden during December 2021. New plants, lost plants, and some extreme weather.

General

O Tannenbaum

Ever since we moved to Oceanside, we have had a living Christmas tree. After Christmas, those trees are planted into the garden. For the first couple of years, it was easy – there was plenty of room and I still hadn’t decided how to utilize all of the space for a garden. That first year was a Blue Spruce (Picea pungens) and it soon found itself right in the middle of the cutting garden.

Quickly, one criterion for their selection became that they had to be of restricted mature size. A couple more pines and another spruce have since made the list. Then we decided that there was little reason why they even needed to look like a traditional Christmas tree. Why not evergreen shrubs? Last year, the height of our ‘tree’ was only 2 feet. Juniperus pfitzeriana ‘Gold Lace’ performed wonderfully.

This year, we have even departed from the notion of a traditional evergreen shrub, although we have in some senses regressed on some of the previous criteria – it is a tree and it can grow to 20′ to 50′ tall, with a width of 11′ to 15′. So what is different?

Well, it is a palm. Bismarkia noblis was a plant that we purchased a couple of months ago and has been in the house ever since. It is a little sensitive and only just hardy for us. It had also been grown as a house plant, so was going to need considerable adaptation to being outside and we decided to delay that until spring.

We had not planned to be around for Christmas, but with bad weather approaching, we decided to stay put. However, all of our Christmas decorations are in storage and so these are all the pitiful decorations we could manage. Still – it is the thought that counts.

The Complete list so far

2015 – Picea Pungens

2016 – Pinus thunbergii ‘Thunderhead’

2017 – Picea pungens ‘Gebelle’s Golden Spring’

2018 – Pinus parviflora ‘Cleary’

2019 – Pinus densiflora ‘Golden Ghost’

2020 – Juniperus pfitzeriana ‘Gold Lace’

2021 – Bismarkia nobilis

General

Bay Area Garden Tour

Last week I had to attend a conference in San Francisco. Not being comfortable about being squeezed into a small aluminum tube with 150 strangers of unknown vaccination status, we decided to drive from Oceanside, Oregon down to San Francisco. That being the case, it provided the perfect opportunity to visit some gardens and do some plant buying.

UC Davis Arboretum

On the way down, we stopped at the UC Davis Arboretum and public garden just outside of Sacramento. It is a wonderful walking path along what used to be the north fork of Putah Creek, but now is a controlled lake/waterway. The garden is split into different regional areas, most of them associated with Mediterranean types of climate. That means areas that focus on South Africa, Australia and New Zealand.

UC Davis - Lake walk — UC Davis – Lake walk

The walk around the lake is three or four miles, but we only did selected parts of it. Given that this is totally open to the public, this is a wonderful gift to the city. My only complaint is that it really doesn’t serve as an arboretum because almost nothing is labeled. Its ability to teach is limited by this. There are areas where signage does help people understand things like the bio swales and the role of certain plants.

UC Davis - Quercus mosaic — UC Davis – Quercus mosaic

UC Santa Cruz Arboretum

After the conference, we headed south along Route 1 to Santa Cruz. This surfing town is home to one of my favorite arboretums. At the Arboretum and Botanic Garden, the focus is plants that do well in Mediterranean climates and has a very extensive Australia garden and South African garden. The Australian Garden makes up over half of the total area and it has a wonderful display of Protea family members as well as many other trees and shrubs.

Everything is well labeled, and the plants are generally left to grow as they would in the wild. Little is pruned or shaped as they might be in a garden. The arboretum is associated with an extensive growing program. Many of the Australian plants come here first for trials to see how well they do in our climate and then they push them out into the nursery industry.

Some Rare Plants

They also have some plants that they are trying to work out how to effectively propagate. One of my favorite plants at this time of year falls into that category – Astroloma foliosum “Candle Cranberry”. What I would give to have one of these. While there we talked to Ferd, a volunteer in the garden and a director of the program. He talked about how it eludes them so far, and they have only managed to grow three from seed – of which he is the proud owner of one of those.

Ferd also showed us one of their prized possessions. The Wollemi Pine, one of the world’s oldest and rarest plants dating back to the time of the dinosaurs. This plant is being brought back from the brink of extinction as it was down to only 100 plants in the wild. The arboretum is now sending seed back to Australia for further conservation efforts.

Wollemi Pine with both Male and Female flowers

Attached to arboretum is their plant and gift shop – Norries. They sell many of the plants they propagate and at very reasonable prices. Plants can be ordered online for pickup, or just browse through what they have available. Many of them are in very limited supply, so I reserved some plants several weeks before the trip started.

UC Berkeley

The next day, we headed up the East Bay with the first stop being the arboretum at UC Berkeley. This is high up in the Berkeley hills overlooking the San Francisco Bay. Parts of the garden feel very old, with towering mature specimens, while other parts looked to have been more recently refreshed. Along with the Mediterranean climate areas, they also have an Asian area.

The Australasia section seemed to struggle growing many plants from the Protea family. While they did have some nice plants, the soil appeared to be somewhat unsuitable. Treating in some areas, you could feel a spongy soil that was holding a lot of moisture. Admittedly, it had been raining some in the past few days, but I also suspect they were adding supplemental water – something that these plants should not need, or even want.

Ruth Bancroft Garden

A little further north and east in the Walnut Creek area is the Ruth Bancroft Garden. This was once a private garden but now is open to the public and what a treasure it is. This is a dry garden and features succulents of amazing sizes. Many Aloes are in bloom right now, some with bloom stalks towering above you. Even those plants that are not in bloom will surely impress you.

They also have a great selection of plants available for sale, but not propagated from within the garden. While there are some plants that you can see growing and then buy, most of the plants available are not growing in the garden. The selection is in keeping with those shown in the garden.

The Journey Home

We journeyed home with 40 plants packed into the car. Most of them were 1 gallon sized, some larger and a few smaller. It always amazes me how many we can fit in. As we left the Bay Area, we were escaping from an atmospheric river. While there was lots of rain all the ways home, it was nothing compared to what they were expecting. The choice was to go up I-5, where the Siskiyou Pass reaches an elevation of 4310 feet or to go up the coast using US 101. Snow was predicted in the pass, and there were landslides at several places on 101. We chose to confront the snow and bought some chains just in case. Luckily, it was not too bad and we didn’t have to use them, but better safe than sorry.