In these Northern climes, we are always looking for the ‘look’ in our grounds that gives us the illusion that we are actually in a warmer climate. Our summers are nice, warm, dry, etc., but the winters do not allow a lot of choice in regards to having landscaping that actually ‘looks tropical’ in the summer. With a few years of trials and errors, I can give some recommendations, at least in our climate. We are on the northwest interior coast of Washington State. We are NOT on the Pacific Ocean, but in a special zone that is warmer than the actual coast, but at an altitude, 100 ft, that moderates the winter and summer temperatures. Highland Garden House is about 5 miles from the salt water bays and inlets of Puget Sound. We sit on a southwest facing corner lot, on a slope that allows cold air to drain to the flats below. And, surprise, same latitude as Paris! So maybe those in Scotland OR Cornwall can gain some tips from this post. Our temperature extremes here run from 0 f in the winter to 100f in the summer. Normal: 10-20f winter lows, 80-90f summer highs. Stick in photos have black marks every 12 inches, for scale.
I like the Windmill Palm best. Trachycarpus fortunei. I looks good and year around. Slow grower. Water well in the spring/summer to put on growth during the long, warm days; that is the ONLY time it will be growing. Getting any palm past it’s first few winters is the challenge. Tie up and around and cover during weather that is below 20F. Leave covered until March. If it survives a few winters, it will be strong enough to make the rest, it should be too large to cover by then, anyway! As palms get larger and have a more robust root system, they appear to be able to survive lower temps. Of course you can grow palms in pots and bring into a bright, very cool place in the winter. After a few years of that, you can put the palm into it’s permanent place in the ground.
We have palms here in NW Washington that are 30 ft tall. (Other palms I have had luck with: Washingtonia robusta, hardy to 20f (Mexican Fan Palm) , Mediterranean Fan Palm, hardy to 10f (Chamaerops Humilis)
Yes, Bananas! Well, no fruits, but a great leafy effect. Use the hardy banana Musa Basjoo. This ‘tropical’ will die to the ground after the tempuratures are below 25f. But in the Spring will leap to life to create a tropical paradise effect! In November, cut to ground, cover with a square of plastic to keep pounding rains off, and mulch heavy; at least 12 – 18 inches thick. You are putting this root system to sleep for the winter and do not want it to freeze. I have had this plant grow to 8 ft tall after the 3rd year and 7 ft wide. The wind will shred the elephant ear-sized leaves, so a protected place is preferred. The main plant will produce multiple side shoots every year, and so on. I will be digging and
dividing my plant after three years in the ground from a gallon size. Here is more good advice for putting your banana to bed for the winter.
Choose clumping types. Fargesia rufa is reliable here. Hardy to 10f. No protection possible, some die-back in a harsh winter, regrows in spring. Evergreen, slow growing clumping type. Height to 8 ft, width: expands about 6″ per year, so your little plant will get 12″ wider in diameter EACH year. (You do the math!) We prune out some of the canes every year and use them in the garden for markers, stakes and to hold the milk-jug cloches to the ground. The canes that are two years old will be very hard and will hold up several years in garden stake service. When they finally give up, just cut them short and recycle back into the garden!
Many sedums have an exotic effect, even though they are very hardy. My favorite is Sedum spurium ‘Fuldaglut’ Looks good year-round. This sedum will creep along the ground and spread out and down over rocks and walls. The dried flower stalks can be groomed out when they look untidy. Nice red leaves and flower tops. Keep the grasses out of it from day one! If you religiously keep your beds of sedums weeded, you will tear some of the sedum out, too. This does not harm the bed and these pieses can be tossed in another place and many of them will root. The picture was taken in August, showing the beginning of the showy flower stalks. Nice contrast with those granite river boulders.
Any type provides a leafy, sub-tropical effect with all those canes and leaves. Totally hardy almost anywhere. Grapes can be trained onto any support that fits your landscaping. I use 3/4″ steel rebar and keep them low so they do not block my south facing windows. In a warmer climate, you would WANT them to shade those windows; just build some support that is taller.
A diverse genus of which many cultivars do very well here and are STUNNING part of the year and are merely extra fancy the rest of the time! My favorites are Euphorbia characias ‘Tasmanian Tiger’ and Euphorbia characias ‘Glacier Blue.’ Both get the same culture: once established, never add additional water again; after blooming in late spring, cut bloomed-out stalks to base and allow new stalks to grow to replace. It is like a new shrub is always waiting
and ready to take the place of the older stalks! The day you cut out the older stalks, the plant still looks nice, only smaller.
’til next time,
Highland Garden House B & B
501 E. Highland Ave.
Mount Vernon, WA 98273