WEEDS

Priority weeds for volunteers to target in Trelissick Park

Wellington City Council will be carrying out a large amount of weed control in Trelissick Park over the next few years, however they need your help! There are a few weed species which are best controlled by hand as long as the job is done properly. This guide lists 10 key weeds which you can help control, and direction on the best way to do this. Remember if you see these weeds in the park, and they look easy to control now, they soon won't be!

We have categorised the weeds into three groups:

Category 1: Resprouting weeds which need to be removed from the park. Carry these to an entrance of the park and call the WCC weed team (4994444) or contact me, the Adopt a Spot Coordinator.
Category 2: Resprouting weeds that need to be disposed of carefully (hang small amounts in a tree to expose to the sun).
Category 3: Weeds that will not resprout can be spread around the site, or left lying on the ground where they fall. This matches the natural regeneration process and the fallen weeds act as mulch to protect new plants.

1. Tradescantia: Category 1. Wandering willy.
A spreading groundcover which does not seed in New Zealand, instead this plant grows from stem fragments. This weed is an ecological nightmare, but it also causes eczema in some dogs. Trelissick Park is well used by dog walkers, and we would like to keep it that way. To clear Tradescantia pull it out by hand or rake it into a pile. Try to get all broken fragments, and watch that you don't lose any into the stream (this will only spread the problem). Put all plant material into a rubbish sack - and carry to an entrance to the park. Once Tradescantia it is dead or removed, a good covering of grass growth soon after should prevent it coming back. Let me know if you clear a very large patch, and I will ask WCC to spray any residual plant matter.

2. Montbretia: Category 3.
Forms thick clumps which inhibit seedling growth. Pull out by hand, but make sure you get the corms too! If they don't all come out you can use a trowel to dig them up. Leave the remains exposed to the sun to kill off the corms, or remove the corms from the park and dispose of carefully.

3. Climbing asparagus: Category 2.
A nasty creeper which produces small white flowers in early summer, followed by orange berries which are spread by birds. This is a problem on steep rocky slopes, so be careful when trying to attack this one! It is a Banned weed and is a high priority problem. WCC will be spraying this in key areas next year, but we need your help to hand weed any new seedlings you come across. If possible, dig up the tubers too! Let me know if you spot any large infestations.

4. Blackberry: Category 3.
An ongoing problem in the park. Large patches will be controlled by WCC next financial year, but any further growth you will need to grub out, or lop off at ground level and paste the stump with vigilant. Make sure you wear gloves when dealing to blackberry.

5. Wattle and Sycamore seedlings: Category 3.
Wattle is an evergreen shrub/tree, which establishes quickly and displaces native plants. Sycamores are large deciduous trees which produce 'helicopter seeds' that are efficiently dispersed by wind. WCC will work on controlling wattle and sycamore trees next financial year, but the small seedlings are very wide spread. Pull these out by hand and expose to the sun. Wattle seeds stay dormant in the soil for years, so this will be an ongoing task!

6. Karaka: Category 3.
A native tree which is probably not endemic to the Wellington region. It has been reported that given the chance Karaka will replace the native vegetation of an area through aggressive regeneration - especially areas recently cleared of Tradescantia. For this reason we encourage you to pull out Karaka seedlings if they are beginning to form a dense grove. This plant does supply fruit for Kereru and other birds so will not be completely removed, but we may start to thin out mature infestations.


7. Pine and Macrocarpa: Category 3.
Large exotic trees which do not allow native revegetation. Again there is not a lot we can do with the larger trees, but we can stop the seedlings causing more problems. Pull out any seedlings you see.

8. Boneseed: Category 1.
This weed likes exposed sites, and seed germination is stimulated by fire. It is more of a problem in the bottom half of the park than the top. This is a tough, highly invasive plant so is a high priority to remove. Cut it out, and put the cut branches in a rubbish sack. Paint the stump with vigilant. Seeds can remain viable for up to 10 years, so it is important to dispose of all plant matter correctly. Smaller seedlings can be pulled out, and hung in a tree.

9. Cherry: Category 2.
A deciduous fruit tree, which spreads by dropping branches which sprout. This is not yet a major problem in the park, but is a high priority as it is quickly distributed by birds. Please weed out any seedlings you come across. Small trees can be cut and pasted with vigilant, but as with willow, make sure you paste both the stump and the cut stem and keep it off the ground. It can then be left to rot down naturally.

10. Tree Lucerne and Karo: Category 3.
Both planted in the park historically to attract birds. These trees are beginning to spread, and do not naturally occur in our landscape. Like Karaka we may thin out some large trees in the future, but please weed out any Karo or Tree Lucerne seedlings in the mean time.

Remember to keep piles of weeds clear of the track, and out of the flood zone. If weeds end up in the stream they spread downstream.

WCC has spent its budget for the 06/07 financial year controlling the willow in the stream, but will be able to provide some assistance with Tradescantia. WCC does have a good budget for weed control in Trelissick Park for the 07/08 financial year, which begins in July.

It is a good idea wherever possible to remove weed cuttings and fragments from the Park. Piles of cut material can harbour other weeds, cuttings from category 1 and 2 weeds can resprout, and thick piles prevent any native seedlings from germinating underneath. The best method of disposing of greenwaste is via a hire bin or bag which then goes to the landfill, or at home in your compost. Like many of Wellington's parks and reserves, a common source of destructive weeds in Trelissick Park is from people dumping their greenwaste. Please don't contribute to the problem, and dispose of your greenwaste thoughtfully.

The other important source of invasive weeds is plants escaping from gardens and growing wild over the back fence. If you live near a reserve such as Trelissick Park, please have a look in your garden and have a think about plants that may become potential weeds in the future. It doesn't take much for a fast-growing climber to spread seed and escape into the native bush beyond your garden.

Other category 1 weeds include: Old Mans Beard, Japanese Honeysuckle (see November newsletter), & Banana Passionfruit vines. If you spot any of these weeds please let me know so they can be dealt with appropriately.
Category 2 weeds include: Ivy, Ragwort, Briar Rose, Cotoneaster.
Category 3 weeds include: grasses, bidibid, pampas, broom etc.