Bottlebrush With Open Canopy and Yellow

Q. I have a bottle brush shrub that is open and getting yellow. What to do?

A. The Australian bottle brush plant is sold as a shrub but can reach heights of 25 feet so it can also qualify as a small tree as well. Bottlebrush varies from dwarf types to trees and flower color from red to white to pink. 

Flowers of the red bottlebrush.

Later the flowers produce this which are seed capsules.

Dwarf Types

Just don’t use dwarf types like ‘Little John’ if you want a larger tree sized plant. In tree form it can be used on single story homes for shade. To be on the safe side plant it away from hot walls. There is a weeping form and a non-weeping form as well as dwarf varieties. Also flower color can range from yellow to red and shades of red to pink and white.

One of the dwarf types, don;t know which one, with freezing damage.

Yellowing Leaves

            It oftentimes has a problem. Yellowing of the leaves oftentimes occurs when the soil is low in nutrients as well as its organic matter content. Fix yellowing by applying a landscape fertilizer every year in the spring and combine it with an annual application of chelated iron. Enriching the soil with organic matter is done when you used small rocks by raking them back and applying a thin layer of compost to the soil, wetting it, and raking the rocks back. Large rocks may not need raking. The compost and fertilizer will just wash through it to the soil.

One of the iron chelates, EDDHA. I prefer this type of iron chelate because it is stable regardless of the soil pH. Other iron chelates like EDTA and DTPA iron chelates become ineffective at soil pH above about 7.6. Apply it early in the growing season when you make a fertilizer application.

Increase Density of Canopy

            To improve the density of its canopy, make sure it gets enough water. The plant grows best if treated as a “mesic” plant rather than a desert or xeric plant. It grows well when surrounded by lawn. Water should wet the soil about three or four feet in diameter to a depth of about 18 to 24 inches deep each time. Water it as you would any mesic plant such as ash, bottle tree, African sumac, and others. As this plant approaches ten feet tall then wet the soil about five to six feet in diameter. Another possibility might be low soil organic content. So rake the rock away and put a thin layer of compost on top of the soil, water it in and replace the rock.

Pruning to Tree

            To get a small tree out of this, remove the lower limbs when it is 3 or 4 four feet tall so that the canopy occupies about 2/3 and the trunk is about 1/3 of its height. Plant it at least five feet away from hot walls or it will fry. Also in the desert remove lower limbs slowly as the lower limbs touch the ground. Otherwise the trunk may get sunscald.

How to Prune My Blackberries?

Q. Last summer I planted one blackberry bush in my little garden plot.  I got about 10 blackberries and they were delicious.  The problem I have is how to prune it.

Avocados High Risk in Las Vegas Area But If You HAVE to Plant One....

Q. Do you have recommendations/suggestions for new avocado and lime tree plantings for Las Vegas? I currently have a Meyer lemon tree which is doing great.

A. I don't like to recommend lime or avocado for this climate, particularly avocado, unless you have a very warm spot in the landscape that can give off a lot of winter warmth and protection from winter winds.

            These plants are very tender during the winter here and the chances of losing them due to winter cold is extremely high. That being said, if you decide to move ahead with a lime then any of the limes would be a good choice depending on your preference. Rangpur and red limes, although cold hardy, are not limes at all but could be used as a substitute. To my knowledge there is little difference in the true limes abilities to make it through the cold here so that would not be a consideration.

            As far as the avocado goes, I would select a smaller selection to give it a better chance of surviving. Make sure the rootstock is also cold tolerant or you could lose the roots while the top did not freeze. Here are some recommended cold hardy varieties from a Texas website: http://toptropicals.com/html/toptropicals/articles/fruit/varieties_avocado.htm

Cold hardy varieties:

Brazos Belle: Produces medium-large, purple-black long fruit. Season: October-November.

Fantastic: Produces green, paper thin skin, supposedly the most most cold hardy of all. The fruit has a creamy texture.

Joey: Selected by Joey Ricers in Uvalde, Texas (just outside of San-Antonio). Produces medium size, egg shaped purple-black fruit. It has excellent flavor. Heavy bearer. Season: September-October.

Lila: Produces medium size, green fruit. Season: September-October. Don't confuse this variety with Lula, which is popular Florida variety and commonly used for rootstock. (Lula is cold hardy to 25F)

Poncho: Produces medium to large green fruit. Cold hardy to 15F

Lilac Pruning and Selection for the Desert

Q. My daughter has just moved into a house that has old growth lilacs and we need to know how to prune them without causing too much stress on the plants.  Do you have any ideas?

A. By the way, Persian lilacs grow and bloom better here than the common lilac and are very showy. However, the lilac variety “Lavender Lady” requires less chilling and blooms very well here. These are not plants for rock landscapes but should be in the high water use zones and the soil should be amended well at planting and covered with organic mulch.

            For good-looking lilacs always start pruning at the bottom of the shrub. At the bottom, identify the two or three largest stems coming from the base. Remove them with clean cuts close to the ground. I can't see the shrub but several smaller stems should remain that supports flowering for next year.

            What you are trying to accomplish with many woody shrubs is to renew the shrub with new growth on a constant basis. You do this by removal of the largest stems close to the ground. This should cause smaller and newer growth to originate from the base keeping the shrub green, juvenile and full of flowers and leaves from top to bottom.

            Every couple of years, repeat this type of pruning; remove the largest stems at the base. If done correctly, this will keep the shrubs renewed and looking good. This is all you need to do unless you have some crossed or broken branches at the top that you need to remove.

            Don't forget to fertilize the with a good quality fertilizer made for woody plants. Fertilize plants whenever you take anything from them (pruning) or they give you something (flowering). So when you’re pruning or they bloom for you, you need to give back to them lightly in the form of a fertilizer. You can use fertilizer stakes. Put fertilizers close to the emitters or their source of water. Do this in late January through March and make light applications right after they finish blooming. I hope this helps.