Slug-Resistant Hosta Varieties

Top row (left-right): 'Halcyon', 'Fire and Ice', 'Blue Angel'. Middle row (l-r): 'Sagae', H. sieboldiana 'Elegans', 'June'. Bottom row (l-r): 'Liberty', 'Sum and Substance', 'Patriot'.

Hostas are among the most beautiful and stately of foliage plants for shade gardens but many varieties are severely damaged by slugs and snails feeding on their leaves. The varieties listed above have proven to resist such damage in all parts of the U.S. and are readily available at better garden centers at a reasonable price.

All that they require is well-drained soil enriched with organic matter and regular watering through the summer months. Try to keep most hosta varieties out of the sun during the afternoon hours to avoid burning the leaves. Varieties that will tolerate sun into the early afternoon are 'June,' 'Pathfinder,' 'Sum and Substance,' and 'Great Expectations' to name a few (not all are shown above).

As an extra bit of protection against slugs, sprinkle a small amount of SLUGGO or other brand of iron phosphate pellets around the base of your hostas and other emerging perennials to prevent damage. Iron phosphate is safe to pets and wildlife and remains effective after raining. Cheers, Tim

Dahlias

Clockwise from Top Left: Dahlia 'Sylvia J', 'Moonfire', 'Little Show Off', 'Bishop of Llandaff', 'My Joy', 'Fascination', 'Seduction', 'Pink Suffusion' and 'Hayley Jane'(center)

There are few plants that offer the range of color, size and form that dahlias can provide. Their ease of culture and versatility make them a favorite to gardeners of all types. Many of us enjoy dahlias for their long bloom period in late summer and the abundance of cut flowers that they offer. They are also easy to share with friends and neighbors, and the parent plants benefit from being divided every few years.

Many of the single and collarette types are popular for those looking to integrate dahlias into mixed borders or bedding schemes with other plants, especially those with dark foliage like 'Bishop of Llandaff' and 'Moonfire.' Although it is my feeling that all dahlias should be staked for support, these types tend to flop less after summer rains and their simpler flower forms contrast well with a wide range of other flowers. That being said, there are no 'gardening rules' where dahlias are concerned and they are the perfect plant for those who are more adventurous with color. Feel free to be as bold and exhuberant as you like. The possibilities are nearly endless when you combine them with other summer-blooming flowers. To hobbyists and breeders, growing dahlias can take on an entirely different meaning as they try to produce plants with perfect form and larger flowers or try their hand at breeding new varieties.

To succeed with growing dahlias, it is imperative that they be planted in moist, well-drained soil that has been enriched with organic matter such as compost or well-rotted steer manure. They also benefit from supplemental feeding with alfalfa meal and an all purpose-organic fertilizer. Deep, regular waterings are crucial during their bloom period from mid to late summer and regular deadheading will proliferate their overall bloom. For best results, try to site dahlias where they will receive at least four hours of direct afternoon sun. Less sun will result in diminished performance. Dahlias may also experience powdery mildew (a fungal disease on the leaves) when they are drought-stressed or if they are sited in an area with poor air circulation (usually shaded).

If purchasing dahlias as dormant tubers in February or March, I would recommend potting them into small containers and storing them in an unheated garage or frost-free location until the beginning of April. At this point, go ahead and plant them outdoors if the ground isn't frozen.

Many reputable dahlia vendors will be selling their wares at the upcoming Northwest Flower and Garden Show beginning on Feb.18th (see 'Events'). A few to note are: Connell's (Tacoma, WA), Dan's Dahlias (Oakville, WA), and Swan Island Dahlias (Canby, OR). Cheers, Tim

Assessing Cold Damage To Plants

Left:Phormium 'Sundowner"; Right:Hebe 'Amy'


Many gardeners in the Seattle area have noticed considerable damage to landscape plants such as phormiums (New Zealand Flax) and hebes due to our recent December snowstorm. The extent of this damage is the worst that I have witnessed since the winter of 1990. Among my own plants, Phormium 'Yellow Wave' and a variegated form of Pittosporum tenuifolium appear to have been affected as well. The combination of snow, moisture and several days of subfreezing temperatures created the perfect conditions to either severely damage or even kill a large number of marginally hardy plants in our region.

It is likely that most marginally hardy plants that had been sited in wet or poorly drained areas would have perished in this most recent event. Others at risk are those that were planted last fall and were not well-rooted. The plants that have the greatest chance of survival are those that were established and had good drainage to begin with. Nevertheless, before jumping to any immediate conclusions, I would perform a thorough examination of any plants in question. Once you see how severe the damage is, you can make a decision based on whether the plant can recover within a reasonable time period or if the cost of its replacement is acceptable. Since many of these plants are in very prominent locations, you may not want to wait until summer to fill certain voids left by any dieback.

When inspecting a phormium, even if all of the large grass-like leaves may be brown and/or dead, pull firmly on the leaves near the base of the plant. If they are firmly attached and do not pull away like limp muck, there is a good chance that the roots are in good shape and the plant should regrow from the base by summer. I would go ahead now and cut the leaves back to roughly 6" from the base. If another cold snap is expected later this winter, I would plan on covering the crown with pine boughs, burlap, or other protective covering.

To properly inspect a woody ornamental such as a hebe or Spanish lavender, I would try to wait until late March when temperatures can begin to encourage signs of growth such as budding on the stems below any branch dieback. At this time, you would be safe to prune or shear them back until you can see that the stem tissue is alive. If you scrape the outer bark on the stem with your thumbnail, you can see if the wood is alive if you detect a thin later of green tissue (cambium) just underneath. In the event that the plant is still alive, you must also check to make sure that the base(stem) of the plant is not buried by soil or mulch. If the plant needs protection from the cold in the coming weeks, wrap it in burlap or a sheet.

If your plant appears to have some hope of recovery based on what I've mentioned above, continue to monitor your plants weekly through the spring for signs of life and consider applying a generous layer of compost mulch with a bit of steer manure and all-purpose fertilizer worked in (don't bury the stems!!!). This should encourage growth later this spring when the temperatures outside begin to warm up the soil. For those who wish to resort to water-soluble synthetics (ie. Miracle-Gro), wait until at least early April. I hope that this can offer a glimmer of hope to some but only time will tell. Best of luck to all. I'll try to make my next post more pleasant. Cheers, Tim